How to use Windy.com　Basic.pdf

How to use Windy.com
for sea, river, mountain weather forecast
Crane Techno Related Sites: Windy.com manual

In Outdoor Sports climber, fishing, surfing, diving, etc., the most important thing is the weather.
Climbing and fishing in strong rain and strong wind can lead to accidents and slips.
Therefore, it is necessary to check the weather map released by the approved Meteorological Agency in advance.
However, we know the area weather, but not the point weather in sea, river, mountain .
So we recommend Windy.com.
You can see the weather for each point of the sea, mountains, and rivers at a glance.
What is weather App Windy for fishing,diving,surfing ?

Compare Best Weather Apps for 2023 in USA
You can't control whether the sun is shining, the rain is pouring, or the wind is howling, but these useful Android and iOS apps
can help you prepare for Mother Nature's many faces.
You need an outdoor weather forecast app to check sudden weather changes, cumulative rainfall, snowfall, etc.climber, fishing,
surfing, diving Useful weather forecast web&apps for climbing, fishing, surfing, diving to collect information are below.
①Yahoo Weather
②AccuWeather
③Carrot Weather
④The Weather Channel
⑤Windy

What is windy app？
Currently, "Windy" is the No. 1 weather app that is popular for fishing, surfing, diving, and
mountaineering.
Sometimes, the best way to understand the weather around you is to see it visualized on
your phone screen. That's what Windy offers with detailed maps that let you watch the
weather forecast unfold in front of you.
Windy excels at wind patterns, of course, but the app has 40-plus maps available showing
temperature, humidity and more. You've also got satellite and Doppler info at your fingertips,
plus a hurricane tracking feature that comes in handy during storm season.
Windy is a Czech company providing interactive weather forecasting services worldwide.
The portal was founded by Ivo Lukačovič in November 2014. Initially, the portal focused on
wind animation, currently there are other basic meteorological parameters such as
temperature, pressure, relative humidity, cloud base and additional panels with more
advanced data.
Windy also has a website as well as a free app available for iPhone and Android.

Windy.com Web version
The web version of windy.com, you can visually grasp the weather forecast around the world
from this site.
WEB version：https://www.windy.com/
When you want to check the weather information at home, this web version is convenient
because you can see it on the large screen of your PC monitor.

Windy.com Mobile app version
The Windy app is compatible with both iPhone and Android smartphones.
Please install the Windy app from the App Store or Google Play.
The monitor screen is small, but the functions are the same as the web version, which is
convenient when moving.

Install windy.com app
For iPhone, iPad, and iPod touch, download "Windy.com" from the App Store below.
For android, download "Windy.com" from google play below.

＊Important: Points to note when installing the Windy app! !
If you search for Windy apps, you will find two.
(Windy.com) and (Windy.app).
The original is Windy.com, please install it correctly
Windy.com Windy.app
original

Why is "Windy" so popular?
Windy.com was created as a weather app for hobbyist anglers, surfers, divers and other
outdoor sports who need to accurately predict changing weather conditions.
But over time, this app has become essential for the jobs of those who rely on accurate
weather forecasts, such as farmers, fishermen, sailors, aviators and firefighters.
① Windy covers weather information from all over the world. (42 countries translation
available)
②You can grasp the pinpoint weather information of the place you need.
③Visualize weather data by color and understand at a glance.
④Windy is a non-profit service organization and is free to use.

Windy.com Difference between free version and Premium
The difference between Windy.com Free and Premium (paid version) is as follows.
The paid version allows you to see hourly forecasts, and the frequency of updates is high, so you can get more accurate
information in terms of information accuracy. The free version cannot be used for commercial purposes.

Basic usage of windy.com
① windy.com login/registration
② Main button explanation
③ Display contents of the weather forecast for your current location
④ Windy weather picker
⑤ Display operation of weather forecast on smartphone screen
⑥ windy.com app English localization
⑦ windy.com How to set the unit
⑧ How to add a new layer “seawater temperature” to the menu screen
⑨ How to add a new layer “atmospheric pressure” to the menu screen
⑩ Altitude setting
⑪ How to add to Favorites Windy
⑫ Windy Gallery Select
⑬ Windy Expert mode
⑭ Windy Alert function
⑮ Windy Real-time web live camera
⑯ Windy How to add a webcam
⑰ Windy Meteogram
⑱ Windy Airgram
⑲ Sounding forecast
⑳ Windy Comparing weather forecasts

１.Windy.com login/registration
If you log in and register your e-mail address and password, you can use expert mode and further improve
the functions, so we recommend registering.
To select the screen you want to display, press the “Home”, “Weather Radar &Satellite”, “Menu”, “Search
Location”, and “Profile” buttons on the right.
Home
Weather Radar & Satellite
Menu
Search Location
profile
Right button explanation

2．Main button explanation
To select the screen you want to display, press the “Home”,
“Weather Radar &Satellite”, “Menu”, “Search Location”, and
“Profile” buttons on the right.

3．Display contents of the weather forecast for your current location
When you press the home button, the weather for the next
three days will be displayed at your current location.
You can check detailed information by clicking the orange part and
moving it to the day of the week you want to see.
temperature （℃）
wind force, wind direction
weather
move

Enter the address of the place you want to
know in the search window, the name of
the mountain, the name of the fishing
port is also OK
Weather, temperature, wind speed, etc.
are displayed every 3 hours.
If you press and hold (or right-click on a PC)
any place on the map, a menu like the picture
below will appear, so you can also press
"Forecast for this position" to display the
weather forecast.

"Weather picker" displays the forecast of the selected layer at an arbitrary point as a numerical value.
For example, if the wind layer is selected, the wind speed and wind direction values will be displayed.
In the case of the PC version, the picker can be displayed by right-clicking anywhere and selecting "Show weather
picker", and in the mobile version, long-pressing any position.
In the case of the PC version, You can move the location by moving the mouse pointer near the weather picker and
dragging it when it becomes an up/down/left/right arrow icon.
Also, you need to display the "weather picker" to register your favorite locations.
4．Windy weather picker
Select weather picker Show weather picker move the weather picker

How to zoom in on the screen
Move two fingers apart and perform the operation
"pinch out" (pinch-out, pinch-open) to widen the gap.
How to zoom out the screen of a smartphone
"Pinch-in" (pinch-close) is performed by pinching
two fingers together to narrow the gap.
5．Display operation of weather forecast on smartphone screen

6．windy.com app English localization
①Press Menu. ②Press Settings. ③Press Language automatic and select English.

7.How to set the unit
１． menu button ⇒ Select settings
２．Set the unit of weather information.
３．In the United States, MPH (miles per hour) is often used for wind strength.
4. In the United States, temperatures are expressed in degrees Fahrenheit (℉).
5．For other settings, select the display screen setting as necessary.

How to change other settings
１． menu button ⇒ Select settings
２．A list of other settings will be displayed at the bottom, so select
the settings for the item as necessary.

Other settings
① Wind Animation: Settings for the particle animation displayed on the map. Set by sliding the button left and right.
② Time Format: Select 12-hour format or 24-hour format.
③ English Map Labels: When turned on, the place names on the map are displayed in English.
④ Startup Layer & Location: Settings for weather information displayed when the app is opened or displayed in a browser.
⑤ The weather information of the current location is displayed by GPS, and the weather information of the location
registered as a favorite is also displayed.
⑥ Show latitude/longitude grid: Turn on to display latitude/longitude grid lines on the map.
⑦ Display weather information up to 4 days ahead at startup: When turned on, the weather information for the starting
position above is displayed, and when turned off, the weather information at the start is hidden.
⑧ Direction display: Changed the display of the wind direction of the spot pin that appears when tapping on the map.
⑨ Show all times in UTC: Allows you to change the time display to universal time. *UTC = Coordinated Universal Time
⑩ Smooth satellite animation: When turned on, the satellite animation moves.

Other settings
⑪Language setting (language): Select the language to use.
⑫Delete all data from this device: Delete all data stored on windy.
⑬Notification settings: Settings for notification destinations for weather alarms.
⑭Change the background map: Display when the map is enlarged, the black one is the aerial photo display.

8．How to add a new layer "seawater temperature"
to the menu screen
１） press the menu button
⇒Select other layers
２）Select seawater temperature
Sea water temperature by color
３）Colorized seawater temperature
is displayed

9 ．How to add a new layer "atmospheric pressure"
to the menu screen
１）２） Select " pressure" ３）If you select Isobar, the barometric
contour will be displayed.
１） press the menu button
⇒Select other layers
atmospheric pressure

10.Altitude setting
By default, it displays surface weather information.By adjusting the altitude slider under the layer menu, you
can display wind speeds above 900m, 1500m, 2000m, 3000m, 5500m.
Altitude sliders are visible only when the Wind, Temperature, and Humidity layers are visible.
ground surface wind Altitude 900m wind Altitude 5500m wind

11．How to add to Favorites
You can register frequently visited places as favorites so that they can be displayed
immediately, and search for places from the search window.
① Then the following screen will appear.
so tap ♡ mark and select Add to Favorites.
②Tap the ♡ mark (or profile icon) at
the bottom right of the top screen to
display the list.
③Favorite list

12．Gallery Select
Show gallery of available layers.
１） Press the menu button ⇒ Select More layers
And then is displayed at the top.
When you press the gallery button, the display state of various weather
information is displayed.
Animation moves when you hover your mouse over the thumbnail
You can also add it to the quick menu from here.
Weather radar
Satelite
wind

13．Expert mode
In standard mode, "swell", "swell 2" and "sea temperature" are displayed under the item "wave".
When you switch to expert mode, "swell", "swell 2" and "sea temperature" will be displayed in the same
hierarchy.
Expert mode is easy to use because you can select the weather information you want to display in one shot.
【 Standard mode 】【 Expert mode 】
Expert mode is displayed at the bottom by pressing the menu button and selecting other layers.

14．Alert function
You can set up to receive alerts when any place has certain weather conditions.
Display the weather forecast for the place where you want to receive an alert, tap the ♡ mark displayed at the top
of the main screen, and then select "Alert for this spot".
Alarm condition example:

15. Real-time web live camera
If you want to know detailed local information before you go out, check the images of live cameras in various places.
When you select "Webcam" from the menu, a camera icon will be displayed on the map, so select a camera near the
place you want to move.
①
②
St.pete Beach live image is displayed

Another way is to enter the location you want to check in the "search window" of the Home menu,
and a thumbnail image of the nearby webcam will be displayed, so click it to display the image.
a thumbnail image of
the nearby webcam

16. How to add a webcam
① Select "Webcam" from the menu,
a camera icon will be displayed on
the map, then click any icon to
display the webcam image.
②The following screen will be
displayed, so select Add new webcam.
③Enter the webcam page and image
URL
①
② ③

④Copy the webcam location from
Google Map and enter the latitude
and longitude.
⑤Enter additional information.
enter the latitude
and longitude.
⑥Press the send button to complete
④ ⑤
⑥

＊At ground level it is 1013hPa (1 atmosphere), and as the altitude increases
by 1000m, the atmospheric pressure decreases by about 100hPa.At the
summit of Mt. McKinley (6190m), the atmospheric pressure is about 394hPa.
17. Windy Meteogram
You can see the clouds at different altitudes.
Cloud/Rain:
Clouds are displayed in gray, darker clouds are displayed in
black. You can see the height of the clouds.
Rain:
Regular rain is shown in blue.
Convective rainfall:
It is rain that falls in an unstable atmosphere, and is displayed
in purple. It is a short, strong rainfall that may be accompanied
by thunder, so be careful when climbing.
Snow：
Snowfall, shown in light blue. A useful index for winter
mountaineering.
Flight Level (FL) is one of the flight altitudes used in
aviation."FL" followed by a number in units of 100 feet.
Rain Snow

Switch to [Airgram] in the menu at the bottom of the screen.
Temperature and wind strength by altitude are displayed visually.
18. Windy Airgram
Temperature:
The colors displayed represent the temperature at each altitude
(expressed in hectopascals hpa). Temperature values are
indicated by white numbers.
Wind speed and direction:
The length of the arrow indicates the wind speed. Long barbs
are 10 knots and short barbs are 5 knots.
The wind direction is indicated by the long shaft. The shaft
points in the direction the wind is blowing.
25.7m/s
5.1m/s
2.6m/s
altitude

On the screen, click the right mouse button (on a smartphone, press and hold the screen) and select
[Sounding].
Temperature and wind speed in the sky are displayed graphically. Click inside the graph to see the temperature
and wind speed for that altitude. If you slide the date and time, the graph will change accordingly.
19. Sounding forecast

20. Comparing weather forecasts
In the PC version, you can compare various weather forecasts by pressing the "Compare" button on the bottom
bar with the weather forecast displayed.
In the mobile version, when the weather forecast is displayed, slide the bar at the bottom and a button called
"Compare" will appear.

・The Global Forecast System (GFS) is a global numerical weather prediction system containing a global computer
model and variational analysis run by the United States' National Weather Service (NWS).
・The European Center for Medium-Range Weather Forecasts (ECMWF) is an international organization
established in 1975.Located in Reading, England.
・ Meteoblue (English: Meteoblue) is a weather service founded at the University of Basel, Switzerland. In 2006,
the company started serving customers in the agriculture, solar and wind power sectors.
ICON：An integrated weather forecast and climate model jointly developed by the Max Planck Institute for
Meteorology and Germany's National Weather Service, the German Weather Service (DWD).
The following weather forecasts are displayed.
It is possible to compare four types of weather forecasts.

Windy.com layer types
There are 52 types of Windy layers, so I will mainly explain the layers related to outdoor sports.
PC version display Date: December 5, 2022

Type and description of each layer
1. Display and confirmation of weather radar images
2. Meteorological satellite observation image display and confirmation
3. layer wind
4. Layer Maximum instantaneous wind speed
5. Layer Cumulative air volume
6. Layer Rain, thunder ⇒ "Rain, thunder" "Cumulative rainfall" "New snow" "New snow depth" "Precipitation type"
"Thunderstorm"
7. Layer temperature ⇒ "temperature" "dew point" "humidity" "freezing altitude"
8. Layer wet bulb temperature
9. Layer solar power generation
10. Layer UV index
11. Layer Cloud "Cloud", "Low Cloud", "Middle Cloud", "High Cloud", "Fog", "Cloud Top", "Cloud Base" (Cloud Base)
12. Layer Visibility (Visibility)
13. Layer CAPE index ( convective available potential energy)
14. Layer thermals (Thermals)

15. Layer wave ⇒ swell, swell 2, swell 3, wind waves
16. Layer seawater temperature
17. Layer ocean current
18. Layer tide
19. Layer nitrogen dioxide
20. Layer PM2.5
21. layer aerosol
22. layer ozone layer
23. Layer SO2
24. Layer tropospheric ozone
25. Layer monoxide concentration
26. Layer Dust mass
27. Layer fire strength
28. Layer pressure = mean sea level pressure (MSLP Mean Sea
Level pressure)
29. Layer Extreme forecast
30. Layer Weather warnings
31. Layer Hiking map (Outdoor map)
32. Layer soil moisture
33. Layer humidity anomaly
34. Layer Degree of drought

Press Menu button on the main screen
is displayed, and then select Weather Radar.
1. Display and confirmation of weather radar images
You can see the changes over
time in the animation
strength of radar echo

What is weather radar?
ｄBZ：
A unit that indicates the strength of a radar echo
＊What is weather radar?
By radiating electromagnetic waves from the antenna and analyzing the reflected electromagnetic waves, the position and
density of rain and snow, wind speed and direction can be observed.

Press Menu button on the main screen
is displayed, and then select satellite.
2. Meteorological satellite Display and confirmation of observation images
Temperature: Displayed in degrees
Fahrenheit
You can see the changes over
time in the animation

Meteorological satellite observation image
visible image Infrared image Water vapor image
What is a weather satellite observation image?
You can see the latest movement of clouds as seen from space on meteorological satellite images.
Visible and infrared radiometers mounted on geostationary meteorological satellites observe the strength of
electromagnetic waves in various wavelength bands（From “visible light” that can be seen by the human eye to invisible
“infrared light” (observable regardless of day or night)）
These observation results are displayed as cloud images.

Check before going windsurfing, kitesurfing or sailing.
If you press the wind layer and tap the place you want to check on the map, a weather picker will appear and
you can see the strength of the wind like " NW 7m/s ".
You can see the weather and details by tapping the orange icon on the side.
3. Layer Wind
weather picker
For wind, the average wind speed, gusts and wind direction for that
time are displayed.

Check before going windsurfing, kitesurfing or sailing.
If you press the wind layer and tap the place you want to check on the map, a weather picker will appear and you can
see the strength of the wind gusts like " NW 7m/s ".
You can see the weather and details by tapping the orange icon on the side.
4. Layer wind gusts
weather picker
For wind, the average wind speed, gusts and wind direction for
that time are displayed.

5. Layer Wind accumulation
timeline
Wind accumulation represents the maximum intensity forecast for gusts over the next 10 days.
Essentially, each point on the map represents the strongest or maximum winds predicted for that location over
the next 10 days.
This feature is especially useful for tracking hurricanes and other high wind events.

The wind is constantly fluctuating, getting stronger and weaker in a short time. This instantaneous wind speed
is called "instantaneous wind speed", and its maximum value is called "maximum instantaneous wind speed".
What is wind speed and maximum instantaneous wind speed (gust)?
Wind speed is the speed at which air moves as wind. In surface weather observation, it refers to the average wind speed
for 10 minutes at a height of about 10 meters above the ground, and is expressed as 〇m per second or 〇m/s.
Classification by wind speed
Leftmost color:
In many cases, a color is assigned to each section
so that the wind speed section can be recognized
at a glance.

6. Layer rain, thunder
Layers Rain and thunder are a combination of rain/snow accumulation over the past 3 hours and a forecast of lightning density.
"Rain, Thunder" includes "Rain, Thunder", "Cumulative Rainfall", "New Snow", "New Snow Depth", "Precipitation Type", and
"Thunderstorm".
In “rain, thunder”, the precipitation type is displayed as no symbol rain, snow=＊, or sleet＝！.
Strength is displayed by different colors.
"Accumulated rainfall" and "Fresh snowfall" can display the (expected) cumulative rainfall of "next 12 hours/24 hours/3 days/5
days/10 days".
Rain accumulation
Displays cumulative rainfall
for the selected period
rain, thunder
The weather picker shows the
amount of precipitation.
rain, thunder
The weather picker shows the
amount of snow.
rain
雪
new snow
Displays the amount of snow
accumulated during the selected
period
Rain
accumulation
new snow
snow

“Snow depth” is the depth of snow.
Actual snow depth is affected by many factors such as topography and city.
"Snow depth" can be measured, but "new snow" = "snowfall" cannot be measured directly.
'Precipitation Type' displays rain, frost, mixed ice, snow, wet snow, rain with snow, and ice pellet distribution.
A 'thunderstorm' is defined as the number of flashes of light over an area of 1 square kilometer during the day.
The unit used to express the intensity of a thunderstorm is “l/km2”.
precipitation type
The distribution of rain, snow, sticky
snow, sleet, etc. is displayed.
Snow depth
If you press the skier mark, the snow
depth will be displayed in the
weather picker.
rain
freezing rain
ice pellet
Thunderstorm
The occurrence and frequency of
lightning are displayed in color.

Difference between snowfall amount and snow depth (snow cover amount)
The difference between snowfall and snow depth (snow cover) is shown in the figure below.
"Snow depth" refers to the thickness of the snow cover at a certain point in time.
In meteorological observation, laser beams are used to measure the height from the ground to the snow surface, and the
snow depth is recorded.
On the other hand, unlike rainfall, there is no way to directly measure "snowfall", so the hourly increase in snow depth is
called "snowfall" in meteorological observations.
In plain areas where there is no root snow (old snow), the amount of accumulated snow equals the amount of snowfall.
snow depth snowfall
ground surface
root snow
New Snowし
ground surface
root snow
New Snowし
snow depth
(snow cover)
snowfall

7. Layer temperature
The "Temperature" layer has "Temperature", "Dew Point", "Humidity" and "Frozen Level“, “Wet-bulb temp”
For "Temperature" and "Humidity" as well as "Wind", you can adjust the altitude slider on the right side to display
the temperature in the sky.
The "dew point" is the temperature at which the water vapor contained in the air becomes a liquid (fog) when the
air is cooled.
"Freezing altitude" means the altitude at which water freezes.
altitude slider
Layer temperature Humidity

8.Layer Wet-bulb temp
The temperature measured by wrapping the thermometer sensor in a damp cloth and exposing it to air to avoid
direct sunlight.
The temperature indicated by the wet bulb of a psychrometric hygrometer.
The wet bulb loses latent heat as the water evaporates, and the temperature drops.
A wet-bulb thermometer gives a lower temperature
than a dry-bulb thermometer.
dry-bulb
thermometer
wet-bulb
thermometer

9. Layer Solar Power
Layer The meaning of solar power generation is the amount of solar radiation.
It measures the amount of radiant energy from the sun.
Units are kilowatts per square meter (kW/m2) or watts per square meter (W/m2)

10. Layer UV Index
The UV index (ultraviolet index) is an index designated by the World Health Organization to clearly indicate the
degree of influence of ultraviolet rays on the human body.
UV Index

11. Layer cloud
The layer “clouds” can display weather information such as “clouds” that display all layers and "Low clouds" (100-
2000m above), "Mid-level clouds" (2000-7000m), "High clouds" (over 7000m), "Fog", "Cloud top", "Cloud base"
(Cloud bottom), "Visibility", "CAPE" index"
“Clouds”
Cloud cover is quantified in % and
displayed in gray to white shades.
The amount of rainfall displayed by the
dots is color-coded by a color-coded bar
displayed below the time slider.
"High clouds“
Clouds that occur in high altitudes from
7,000m to 13,000m.made of ice particles.
Cirrostratus, cirrus, and cirrocumulus are
high clouds
"low clouds“
Clouds that extend below 2000m.
Stratocumulus is a cloudy cloud that often
appears in the low sky.
Sometimes you can see streaks of light
through the clouds.
Stratus clouds are the lowest haze-like clouds,
Sometimes it covers low mountains.
[cloud cover]
FEW: Clouds covering 1/8 to 2/8 of the whole sky
SCT: Clouds covering 3/8 to 4/8 of the whole sky
BKN : Cloud covering 5/8 to 7/8 of the whole sky
OVC : Cloud covering the whole sky

“Fog“
Fog generation status is displayed.
“Cloud top“
It is the highest part of the cloud.
Since it is at the top of the sea of clouds,
there are many sunny days at higher altitudes.
"cloud base “
It is the lowest point of the cloud.
Fog type:
Fog
Fog & rime:

If there are many clouds at the foot of the mountain, the height difference between the cloud base and
the cloud top will be large.
This means that the clouds will thicken.
When that happens, the sun's light cannot pass through, and the bottom of the cloud turns dark.
When you see these cloud features, there is a blizzard on the mountain.
Due to the poor visibility and the risk of hypothermia, activities above the forest line should be avoided.
Height difference between
cloud base and cloud top
Height difference between
cloud base and cloud top

Cloud type and height
Upper clouds
Middle level
clouds
low level
clouds
cirrus clouds
Cirrus stratus
Cirrocumulus clouds
Altocumulus clouds
nimbostratus
altostratus
cumulus
cumulonimbus
stratocumulus
stratus

12. Layer Visibility
Visibility is the maximum distance at which an object can be clearly seen with the naked eye.
When the visibility is simply referred to, it often refers to the horizontal visibility, which is the visibility in the horizontal
direction.
Visibility changes and their causes
In meteorology, when the visibility becomes smaller than usual, it is called a visibility disorder, and representative
examples include fog, haze, haze, snow, haze, and yellow sand.
Visibility is often obstructed by rain and snow, but man-made air pollutants (particulate matter) also have a large
impact.
Under these conditions, there are whiteouts that are invisible due to fog, wind and snow, and brownouts that are
invisible due to sand smoke.
Visibility：0.2㎞ Visibility：15.1㎞
whiteout

13.Layer CAPE Index（Convective Available Potential Energy ）
CAPE is effectively the positive buoyancy of an air parcel (mass of air) and is an indicator of atmospheric instability,
which makes it very valuable in predicting severe weather.
Values from 1000 to 2000 can indicate forming of moderate thunderstorms, and over 2000 severe ones.
自由対流高度(LFC)
中立高度(LNB)
LNB:
Level of Neutral Buoyancy The altitude above which a parcel of air cannot rise on its own.
anvil cloud
Convective available potential energy
Level of free convection (LFC) LFC: Afterwards, it rises by itself
Lifted Freeze Altitude (early cloud)
Rising air current vs convection suppression

14.Layer Thermals
Thermal occurrence and altitude, and cumulus cloud occurrence, map color indicates maximum AMSL.
＊AMSL：Above mean sea level
Convective Updraft = Thermal Updraft
Altitude that occurs
Thermal Updraft
pivot
pivot
the air rises
Earth's surface is heated by the sun

15． Layer wave
The definitions of waves, swells, swells 2, swells 3, and wind waves in the weather layer items of Windy.com
are as follows.
Waves: Significant wave height and its period of all wave types combined (swell and wind waves). Close to the
shoreline, the actual height is influenced by the shape of the sea bottom.
Swell1: A swell consists of wind-generated mechanical waves that are not significantly affected by the local
wind at that time. They have been generated elsewhere and some time ago, usually travelling long distances.
Swell2: Secondary swell is produced also by winds far away but in other places than Swell1. It has different
heights, directions and periods than Swell1.
Swell3: Another secondary swell, with different heights, directions and periods than Swell1 and Swell2. More
detailed info about the swells is here.
Wind waves: Wind waves, or wind-generated waves, are surface waves that occur on the free surface of
bodies of water (like oceans, seas, lakes, etc.). They result from the wind blowing over an area of water surface.
Wind waves are generated by the immediate local wind – which gives them the direction. After the wind
ceases to blow, wind waves are called swells.
引用先：Description of weather overlays

What is wave ？
There are two types of waves: wind waves and swells.
①Wind waves: Waves caused by the wind are called wind waves
② Swell:Waves caused by winds in other sea areas are called swells. A typical example of
swells is waves caused by the aftermath of a storm. Swells have a longer period and
longer wavelength than wind waves.
wind wave Swell

wave is a combination of wind waves, waves, and
the effects of topography.
Swell is a swell caused by wind
waves generated in the distance.
Examples of wave, swell, swell 2, swell 3, wind waves
period
wave
height
deflection

swell 2 is a swell caused by wind
waves generated in a distant place
different from the swell 1.
Wind waves are caused directly
by the wind

16.Layer Seawater temperature
Sea surface temperature as estimated for actual time. Close to the shoreline, the actual value is influenced by the shape of
the shoreline and the sea bottom, and also by wind and waves.
Seawater
temperature
As the depth increases, the water temperature usually decreases.
However, near the surface of the sea, there is a layer with a small change
in water temperature in the depth direction.
This layer is called the surface mixed layer.
In the case of Japan, in the summer, seawater near the surface of the sea
is warmed by solar radiation, The surface mixed layer becomes thinner
because the temperature difference between the sea surface and the lower
layer increases.
In winter, seawater is cooled on the surface of the sea, and the upper and
lower layers of water are actively stirred by the wind blowing over the sea,
forming a thick surface mixed layer.

17. Layer current
Surface sea currents as estimated for actual time. Close to the shoreline, the actual value is influenced by the shape of
shoreline and sea bottom. Also, actual surface sea currents can be influenced by the wind.
sea currents
An ocean current is a large current that always flows in a certain direction
in the ocean.
On the other hand, a current in which the seawater changes periodically
due to the tide is called a tidal current.
１ｋｔ＝0.514m/S

18.Layer tidal current
Tidal currents are the only type of current affected by the interaction by the Earth, sun and moon. When the tidal current
moves toward the land and away from the sea, it floods. When the tidal current toward the sea and away from the land, it
ebbs.
tidal current
The tidal current in the Naruto Strait in Japan reaches over 10 knots
(approximately 20 km/h) at the fastest spring tide.
１ｋｔ＝0.514m/S

19. Layer Nitrogen dioxide NO₂
It is generated as a by-product in the combustion process of various substances and the manufacturing process of substances
such as nitric acid.
Regarding human health effects, there is mainly an effect on the respiratory system, and environmental standards have been
established, and the daily average value is within the range of 0.04–0.06 ppm or less.
Nitrogen
dioxide
The image on the left is nitrogen dioxide in Tokyo, Japan, and the distribution of nitrogen dioxide concentration in Xi'an,
China on the right.
Xi'an, China
「WHO global air quality guidelines」
AQG level:
The AQG level is a kind of guideline recommendation, and
when governments of each country adopt it for environmental
standards, etc., it is necessary to consider the situation of each region.
10μg/m3 less Annual
25μg/m3 less 24-hour
Tokyo Japan
source: WHO global air quality guidelines

20. Layer PM2.5 (microparticulate matter)
PM2.5 refers to very small particles with a diameter of 2.5 μm or less (1 μm = 0.001 mm) suspended in the atmosphere.
The causes are soot and smoke from boilers and incinerators, and dust from coke ovens and mineral deposits.
Due to its small size, PM2.5 penetrates deep into the lungs when inhaled through the mouth or nose, causing various health
hazards.
Yellow dust and PM2.5 are different things, and it seems that they are not related, but in fact, if the size is 2.5 micrometers or
less, dust is also included in PM2.5.
PM2.5
Dhanbad India
New York USA
AQG level:
5μg/m3 less Annual

21. Layer aerosol
A mixture of minute liquid or solid particles suspended in gas and surrounding gas.
Aerosol particles are called dust, fume, mist, smokedust, etc., depending on the process of their generation.
A mixture of minute liquid or solid particles suspended in gas and surrounding gas.Aerosol particles are called dust, fume,
mist, dust, etc., depending on the process of their generation.
Aerosol infections are infections caused by pathogen-laden aerosols.
Aerosols can remain suspended in the air for up to three hours, so there is a risk of infection in closed spaces with high
concentrations of aerosols.
aerosol
＊Aerosol Optical Depth (AOD) is the measure of aerosols
Aerosol infection
It's light enough to
float in the air for
hours!
Droplet infection
There is a lot of water
and it is heavy, so it will
fall immediately

The measure of aerosols
Aerosol Optical Depth (AOD) is the measure of aerosols (e.g., urban haze, smoke particles, desert dust distributed within a
column of air from Earth's surface to the top of the atmosphere.
The rate of extinction of the light increases as AOD increases.
Typical atmospheric values are between 0.1 and 0.15.
Source: Aerosol Optical Depth Quick Guide
Difference between aerosol, SPM and PM10
SPM（Suspended Particulate Matter）:
Aerosols are named according to their particle size. Above all, aerosols with a particle size of 10 μm or less are called suspended
particulate matter (SPM).
Japan's environmental standards define SPM as follows.
1) The daily average value should be 0.10 mg/m3 or less.
2) 1 hour value is 0.20mg/m3 or less.
PM10 is adopted as an environmental standard of WHO. However, it includes particles that are larger than SPM due to
different standards.
1) The annual average value must be 15 μg/m3 or less.
2) The 24-hour average value must be 45 μg/m3 or less.

22. Layer Ozone
ozone layer.
Ozone is a gas consisting of three oxygen atoms.
Approximately 90% of ozone in the atmosphere exists in the stratosphere (approximately 10 to 50 km above), and this ozone-
rich layer is generally called the ozone layer.
Since part of the ultraviolet rays from the sun is absorbed by the ozone layer, generally, the lower the ozone concentration in
the ozone layer, the higher the amount of ultraviolet rays on the earth's surface.Conversely, the higher the ozone concentration,
the lower the amount of UV rays on the ground.
Stratospheric ozone absorbs harmful ultraviolet radiation from the sun and protects terrestrial ecosystems.Measurements of
the ozone layer are measured in (DU), with higher values representing more ozone and less UV radiation.
＊The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's
atmosphere. 1mm thickness is 100 Dobson units.
An ozone hole is presumed to have occurred when the measured value of the ozone layer falls below 220 D.U.
ozone layer
ultraviolet rays
ozone hole

23. Layer sulfur dioxide SO2
Sulfur dioxide is a poisonous gas with a burnt match smell.
It is released naturally by volcanic activity and is produced as a by-product of burning fossil fuels contaminated with sulfur
compounds.
The unit concentration is mg/m2.
Sulfur dioxide is colorless and has a pungent odor that irritates the eyes and throat. Breathing high concentrations of sulfur
dioxide may cause breathing difficulties.
The current windy SO2 measurement data is CAMS, which shows sulfur dioxide from the ground to the top of the atmosphere
on a square meter basis rather than per cubic meter, expressed in mg/m2 as the vertical column cross-sectional area density.

Reference article
AQG level:
40μg/m3=0.04mg/m3 less 24-hour
Previously, the source of measurement data was GEOS-5 and displayed "Surface SO2", but now
it has been changed to CAMS.
CAMS ：Copernicus Atmosphere Monitoring Service
GEOS-5： Goddard Earth Observing System Model, Version 5

24.Layer tropospheric ozone (photochemical oxidant)
Ozone generated in the troposphere is "bad" ozone that damages living organisms. Tropospheric ozone (photochemical oxidant)
is also famous as an indicator of photochemical smog.
Atmospheric ozone can be divided into "stratospheric ozone" and "tropospheric ozone". While "stratospheric ozone" protects
human health from ultraviolet rays, "tropospheric ozone" is an air pollutant. As such, it is detrimental to human health and plants.
Weather conditions that tend to increase oxidant concentration are
①Strong sunlight.
②High temperature (daily maximum temperature is 25°C or higher)
③Weak wind (4m/s or less) stable atmosphere
AQG level:
60μg/m3 less 6month
High oxidant concentration may irritate the eyes and throat, resulting
in symptoms such as stinging eyes and sore throat.

25. Layer monoxide concentration (CO)
Carbon monoxide is a colorless, odorless, tasteless gas that is slightly less dense than air.
Tropospheric CO concentration levels are measured by a system called parts per billion volume (PPBV).
If the concentration in the air rises to 0.02% (200ppm), headaches will occur, and if the concentration rises further, poisoning
symptoms such as nausea and dizziness will progress, and in the worst case, death.
潮流
AQG level:
4mg/m3 less 24-hour
3.43 ppm less
1ppm=1000 PPBV =1.1646757 mg / m3
Windy CO data:Carbon monoxide (CO), unlike CO2 and CH4, has a
small contribution to the greenhouse effect and is not a greenhouse
gas.
However,it is closely related to the generation and extinction of CH4
and ozone in the atmosphere, and is a gas that plays an important role
in atmospheric chemistry, indirectly contributing to the greenhouse
effect and global warming.

Units: ppm and ppbv
"ppm" is a unit made by taking the first letter of English (parts per million) meaning one millionth. Like % (percentage), it is
a concept of a ratio with units of 1/1,000,000.ppm is used as a unit for the concentration of gaseous air pollutants (NO2,
SO2, CO, OX, etc.) in the atmosphere.
Normally, it is simply written as ppm, but it may be written as ppmV when emphasizing that it is a volume concentration
(Volume).
When 1cm3 of gas is contained in 1m3 of air, 1m3 = (100cm)3 = 1,000,000cm3 = 106cm3, so the volume ratio is
1/1,000,000 and is expressed as 1ppm.
1ppm is the concentration when a small box-sized gas with length, width and height of 1cm is placed in air of size of 1m
each in length, width and height.
If the concentration level is low and the ppm unit is extremely small, the unit ppbv (parts per million volume), which is
three orders of magnitude smaller than ppm, is used.
1m
1m
1m
1cm
1cm

26. Layer dust mass
Airborne Dust is generally composed of atmospheric particles that originate from a variety of sources, including soil,
weather-lifted dust, volcanic eruptions, and air pollution.
Dust concentration levels are expressed in µg/m3 per cubic meter of air.
Dust is defined by the International Organization for Standardization as “solid suspended matter with a particle size of less
than 75 μm”.
Smoke and Soot is generated when things are burned, etc.
In Japan's Ministry of Health, Labor and Welfare "Guidelines for
Dust Countermeasures in Construction Work such as Tunnels
"The target level of the dust value measured by the dust meter is
2mg/m3 or less (2,000μg/m3) or less

27.fire intensity
This layer displays the fire intensity by measuring the radiant heat generated by the fire.
It also includes radiant heat from residential fires and volcanic eruptions.
The fires in the fiercely fought areas due to artillery fire during the Ukrainian War are also generally
consistent with the parts reported in the media.
Ukraine
＊Unit: thermal radiation （W/m3)

28. Layer Pressure (MSLP Mean Sea Level pressure)
The average atmospheric pressure at sea level.
Atmospheric pressure, also called barometric pressure, is the pressure within the Earth's atmosphere.
Standard atmospheric pressure (1 atm) is 1013.25 hPa above sea level, but since atmospheric pressure is the
pressure that indicates the weight of the air above, it decreases as you go higher.
The ratio of altitude increase to pressure drop is approximately 1.2 hPa for a 10 m rise at low altitudes, which is
calculated to be about 0.5 atmospheres at an altitude of 5,500 m and about 0.3 atmospheres at the summit of
Everest.
If it is covered with high pressure, it will be sunny, but if a low
pressure comes, the weather will get worse.
H
L

Difference between high pressure and low pressure
A high pressure is a place where the pressure is relatively higher than the surroundings, and there is no rule that
it is a high pressure because it is over ◯◯ hPa.
A low pressure area, on the contrary, is a place where the atmospheric pressure is relatively low compared to its
surroundings.
In areas covered by high pressure, descending air currents occur, clouds are less likely to form, and the weather
is good. By the way, high pressure winds blow clockwise.
A low pressure system creates an updraft in which air moves upward from the ground. Low pressure where this
rising air current occurs is a state where clouds are likely to form. The stronger the updraft, the stronger the
clouds and the more intense rain and thunderstorms. Low pressure winds blow counterclockwise.
H
L
Low pressure
High pressure

The magnitude of the atmospheric pressure
Atmospheric pressure is 1013.25 hPa at sea level, and the higher the altitude, the thinner the atmospheric layer and the
lower the atmospheric pressure.
This atmospheric pressure above sea level (1013.25 hPa) is called 1 atmosphere or 1 atm (atom).
It is said that atmospheric pressure decreases by 1 hPa for every 10 m rise.
At the summit of Mt. Fuji, the highest mountain in Japan, the pressure is about two-thirds of the sea level (about 0.7 atm).
atmospheric pressure above sea level
1 atmosphere ( 1 atm)
= 1013.25 hPa
The higher the altitude, the
lower the atmospheric
pressure

Coriolis force
action of rotation (Coriolis force).
自転なし自転あり
north pole
South pole
H
L
rotation of the earth
Equator
no rotation with rotation
H H

29.Layer Extreme forecast
A layer that predicts extreme abnormal weather in different colors and
percentages for each wind, temperature, and rain.
Wind forecast Temperature forecast Rain forecast
Colorization and
Numericalization (%)
Colorization and
Colorization and

30.Layer Weather warnings
Weather alerts are issued by national meteorological agencies in the form of "CAP alerts“
However, it currently covers only some regions such as Europe, the United States, and Russia.
Common Alerting Protocol?
The Common Alerting Protocol (CAP) is an XML-based data format for exchanging public warnings and emergencies between
alerting technologies. CAP allows a warning message to be consistently disseminated simultaneously over many warning systems
to many applications, such as Google Public Alerts and Cell Broadcast. CAP increases warning effectiveness and simplifies the task
of activating a warning for responsible officials.

31. Layer Outdoor map
It can be used as a hiking map using Open Street Map.
Open Street Map also displays mountain trails and hiking routes in an easy-to-understand manner.
【Google Map】【OpenStreetMap】
mountain trail, hiking route
＊OpenStreetMap：
OpenStreetMap is a collaborative project to
create a freely available and editable world map.
Mountain trails
and hiking routes
are not displayed

32.Layer Soil moisture
Readily available soil water represents the amount of water available to plants as a proportion of the maximum
soil water content that can be permanently held within the given soil column.
Units are % where 0% represents no water available to plants (i.e. wilting point) and 100% represents water
content held in the soil after excess water has drained away (i.e. field capacity).
In general most plant species cannot survive values close to 0%, at values below 30% visible signs of water stress
will be apparent on most plant species and at values below 50% (i.e. stress point) plants start to be limited by soil
water availability.
Mongolian State Japan

Display of soil moisture
The amount of water contained in the interstices of soil is called moisture content. The amount can be expressed either by the ratio of the
water content Ww to the dry weight Ws of the soil (moisture ratio) or by the ratio of the water content weight to the wet weight W of the
soil (moisture content). Water content is usually expressed as moisture ratio .
Moisture ratio of soil in its natural state is 5 to 30% for sandy soil and 30 to 80% for cohesive soil. Soil has different engineering properties
depending on its water content, so it is important to know the water content ratio of the soil in order to understand the condition (property)
of the soil.
The display and measurement methods of soil moisture content are not standardized, and there are various display and
measurement methods.
Display content formula Note
moisture ratio(%) Displays moisture weight as a
percentage of dry soil weight
Water weight/dry soil weight x
100w=Ww/Ws×100w is the water content,
Ww is moisture ratio contained in the soil,
and Ws is the weight of the dried soil
Mainly used in agricultural and civil
engineering fields
moisture content(%) Display the moisture weight as a
percentage of the wet soil weight
Water weight/wet soil weight x
100w'=Ww/W×100w' is the moisture content,
Ww is the weight of water, and W is the
weight of soil plus water.
"Soil moisture" commonly used on farms
PF value(Water
retention of soil)
A value that expresses the degree
of strength with which water in soil
is attracted by the capillary force of
soil
A pF meter measures the force required for a
plant to absorb water from the soil.
In the case of upland fields, the pF value is
usually 1.5 to 2.7 (effective water for
growth).
*Utilization of soil moisture by plants Soil moisture includes gravitational water flowing out of soil, capillary water retained in capillaries in soil pores, and
moisture absorption water adsorbed on the surface of soil particles. The roots of crops use capillary water stored in the soil interstices, and the total
amount of available water varies greatly depending on the soil structure.

Windy joined forces with CzechGlobe (Global Change Research Institute CAS) to forecast global drought
Millions of people globally are affected by drought every year, it is a natural climate cycle, which is characterized by the lack
of precipitation, resulting in a water shortage. Drought is a phenomenon that always occurs on our planet in some form at
a given time and can have serious impacts on people’s health, society, economies, agriculture and environment.
We believe that having a tool allowing professionals as well as regular users to analyse current drought situation could
greatly improve efforts to cope with drought and making appropriate decisions.
There are three layers: soil moisture, moisture anomalies, and drought intensity.
Help us to drought impacts in your
region for a safer world
* Displayed in the PC version.

33.Layer Moisture anomaly
Available water deficit is the amount of water in mm/inch per the visualized soil column that is missing (or is in
surplus) compared to the common levels (average of 1961 to 2010) of available water at the given site and time
of the year. Negative values represent less water than usual while positive values represent a higher available
water amount than is common.
Negative values common levels positive values

34.Layer Drought intensity
Drought intensity compares the actual amount of water available to plants with the values recorded for the
given area during the same time period of the year between 1961 and 2010. Each drought intensity class
represents a particular drought period return probability.
The drought is severe!
National Oceanic and Atmospheric Administration
Drought severity is classified into five levels: (D0)
extreme drought, (D1) moderate drought, (D2)
severe drought, (D3) extreme drought, and (D4)
unparalleled drought.
D0 D1 D2 D3 D4

① Particle animation
② Pressure Isolines
③ My favorite
④ Reported wind
⑤ Reported temperature
⑥ Forecasted weather
⑦ Airport
⑧ Paragliding spots
⑨ Kite/WS spots
⑩ Surfing spots
⑪ Web camera
⑫ Air quality
⑬ Radiation
⑭ Tide forecast
⑮ Active fire
⑯ Radiosondes
⑰ Empty map
⑱ Temperature isolines
⑲ Freezing altitude isoline
⑳ Geopot.height
Types and descriptions of the display on the map

①Particles animation of the display on the map
"Particle animation" is on by default, turning it off will not show the wind flow arrow animation.
With this function, you can visually grasp the flow of the wind in that area, which is convenient.
In addition, it is useful for disaster prevention because it can grasp the wind flow of low pressure and typhoon.
Low pressure, wind flow of typhoon
Particles animation
Mobile version PC version
Particles animation

②Pressure isolines of the display on the map
When “Pressure Isolines” is turned on, the isolines of atmospheric pressure is displayed. Isolines are lines that connect
points of equal atmospheric pressure on a surface weather map.
Wind blows from areas of high pressure to areas of low pressure on isolines. The closer the isolines are, the steeper the slope
of the atmospheric pressure and the stronger the wind.
The interval between isobars narrows near the center of a low pressure and widens near the center of a high pressure.
Wind blows from areas of high pressure
to areas of low pressure on isobars.
Pressure isolines
Pressure isolines

③My favorites of the display on the map
When you click "Favorites", the registered "favorite" places are displayed as ♡ marks on the map.
If you click the ♡ mark, the weather tag of the "favorite" point will be displayed and you can know the weather
immediately.
Weather display for favorite points
My favorites
♡ marks

④Reported wind of the display on the map
Displays the reported wind measurements of each country's stations listed in the International Point List
(under WMO).
Also, there are Modis and ad type as station types.
Station madis-AR664
Reported wind
＊WMO:
The World Meteorological Organization (WMO) is a specialized
agency of the United Nations responsible for promoting
international cooperation on atmospheric science, climatology,
hydrology and geophysics.
＊Modis:
Moderate Resolution Imaging Spectroradiometer

⑤Reported temperature of the display on the map
Displays the reported temperatures (measured values) of stations in each country listed in the International
Station Number Table (under WMO jurisdiction).
Also, there are Modis and ad type as station types.
station ad-KFPR
Reported temp
＊WMO:
The World Meteorological Organization (WMO) is a specialized
agency of the United Nations responsible for promoting
international cooperation on atmospheric science, climatology,
hydrology and geophysics.
＊Modis:
Moderate Resolution Imaging Spectroradiometer

⑥Focasted weather of the display on the map
Although it is simple, you can check the weather information of each city at a glance.
PC version Forecasted weather Mobile version Forecasted weather

⑦Airports weather of the display on the map
Click the airplane mark to turn it on to display airports and heliports around the world, and click the corresponding airport or
heliport to display maps of airports and heliports, weather information, webcams, and (NOTAM) aviation information.
＊NOTAM is a type of aviation information, and is information about settings, conditions, changes, etc. related to aviation-
related facilities, operations, methods and dangers. Acronym for "Notice To Airmen or "Notice To Air Mission".
airports
heliport

Rwys,info: Displays information such as airport locations and runways
METAR： It is a type of regular aviation live weather report format, weather report format, and is a format
for reporting aviation weather information in alphanumeric characters.
It is also used by meteorologists for weather forecasts. Derived from French.
METAR displays the current weather conditions around the airport (date and time of announcement, wind
direction and speed, visibility, precipitation, runway visual range and visibility obstruction phenomena, current
weather, cloud cover, cloud height, temperature dew point, atmospheric pressure, etc.) .
The corresponding airport is indicated by the ICAO international four-letter abbreviation.
*ICAO is an abbreviation for "International Civil Aviation Organization".
TAF: Terminal aerodrome forecast、TAF can know the weather forecast around the airport from 0 to 27
hours ahead.
You can check the weather information and typhoon information on the day you board the plane in advance,
so it will be useful for sightseeing and business trips.

⑧Paraglider spot of the display on the map
The world‘s recommended paragliding spots are displayed. Weather information is displayed when you click the
corresponding point.
Paragliding spot Weather information for paragliding spots
Paragliding spot

⑨Kite board、windsurfing spot of the display on the map
Recommended points for kiteboarding and windsurfing around the world are displayed.
In addition, weather information is displayed when we click applicable point.
Kiteboarding and
windsurfing spots
Weather information
Kite/WS spot

⑩Surfing spot of the display on the map
Pressing the surfing icon will display registered surfing points around the world.
Weather information is displayed when you click a point. However, PC version only.
In addition, the information of The Stormrider Surf Guides is displayed.
Surfing point is displayed Displays weather information

⑪webcam of the display on the map
Pressing the webcam icon will display the points of registered webcams around the world.
Click the point to view the webcam image.
Show webcam point Show webcam image

⑫Air Quality of the display on the map
The atmosphere is the gas that covers the surface of the earth in layers, and the air quality index is an index that
conveys the status of daily air pollution to citizens in an easy-to-understand manner from the perspective of
health effects.
Measurement results are expressed in numerical values such as ppm and μg/m3."Air Quality" on the mobile
version, and "Air Chamber Observatory" on the PC version will be displayed.

American Air Quality Index:
Windy displays the Air Quality Index (AQI) of the United States Environmental Protection Agency (EPA).
The AQI of the United States Environmental Protection Agency (EPA) has six levels, and when the index
exceeds 100, it is said that the Sensitive Groups (sensitive groups) are affected. The Sensitive Groups for
each contaminant are as follows.
Ozone: people with lung disease (respiratory disease), children, the elderly, people exercising outdoors
Particulate Matter (PM10, PM2.5): People with lung and heart disease, children and the elderly Carbon
monoxide: people with heart disease Sulfur dioxide: people with asthma
A value exceeding 100 is considered an important criteria for judging health effects.

⑬Radiation dose of the display on the map
There are various types of radiation such as "alpha rays", "beta rays", "gamma rays", "X rays" and "neutron rays".
Radiation is harmful to living organisms and, depending on its intensity, can cause death.
Radiation dose points displayed
Display of radiation dose at
measurement points
Units of radiation dose:
The basic unit is sievert (Sv)
millisievert (mSv), which means 10-3
Microsieverts (μSv) meaning that 10-6
microsieverts (nSv) meaning that 10-9
is usually used.
Long-term exposure to levels up to 2 000 nSv/h is
generally considered to be non-threatening to health.
source：EURDEP
( EUropean Radiological Data Exchange Platform )

According to the 2007 recommendations of the International
Commission on Radiological Protection, the upper limit of exposure
for ordinary people (including children) is 1 millisievert (1000
microsieverts) per year.
Ionizing radiation are capable of ionisation of atoms or molecules in
living cells and thereby damage their genetic material(DNA). In the
event where the cell is not repaired correctly, the cell may die or
become cancerous. However, our cells have adapted to regularly
check for damage to the cells and incorporate repair mechanisms if
any is discovered. Hence receiving small dose of radiation will have
little effect on your body.
It is estimated that a person will naturally receive around 2.4 mSv of
radiation dose per year. The figure on the left is a dose reference
chart that showcase some notable radiation dose exposure.
Guideline for radiation dose

⑭Tide forecast of the display on the map
Pressing the tide forecast icon displays registered tide forecast points around the world.
Clicking on a point will display the low tide, high tide time, and tide level at each point.
If you press the time series button, you can see the tide for each hour.
Tide forecast point display Tide forecast Time and tide level display Time series data
time series button

Tide forecast tide graph
The tide at each point is brown for low tide and light blue for high tide, so you can see the tide status with the high
and low tide mark.
H is high tide, L is low tide.
Low tide
High tide
[Low tide mark]
[High tide mark]
Low tide
High tide

⑮Active Fires of the display on the map
Location information during fires is provided by the Global Fire Assimilation System (GFAS) and displayed on the
screen.
The Global Fire Assimilation System (GFAS) detects radiant heat emitted from fires with satellite sensors and
measures it as fire radiant power (FRP).
The unit is [mW/m2].
PC version Mobile version

⑯Radiosonde of the display on the map
A radiosonde is a radio-equipped meteorological observation device that is mainly attached to a rubber balloon
and flown in order to obtain data such as temperature, humidity, and atmospheric pressure up to an altitude of
about 30 km while on the ground.
When the radiosonde is clicked, a point ○ is displayed.
Radiosonde measurement data (Emagram) is
displayed by clicking on the part you want to check.
dew point
dry adiabatic line

What is an emagram?
An emagram is one of the adiabatic diagrams (thermodynamic diagrams) used in weather.
It plots the relationship between air pressure, temperature, and dew point above a certain point on a graph
with temperature on the horizontal axis on a constant scale and atmospheric pressure on the vertical axis
on a logarithmic scale. It is used to evaluate the stability of the atmosphere above a certain point.
The thin red line is the dry adiabatic line, which shows the temperature
change when the air near the surface is virtually raised.
Stable atmospheric conditions:
If the observed value shown in orange ① at the same altitude shows a
higher temperature, this means that when an updraft is generated for some
reason and the air near the surface is lifted, the temperature of the lifted air
is higher. means lower. Air that is colder (more dense) than its
surroundings is heavier, so no updraft can develop. Such a situation is said
to be "stable atmospheric conditions".
Unstable atmospheric conditions:When the observed value ② is below the
dry adiabatic line of the red line (the lifted air mass is warmer than the
surroundings), the air mass gains further buoyancy and an upward flow
develops. This is called "the atmosphere is unstable", and phenomena with
heavy precipitation such as cumulonimbus clouds are likely to occur in such
places.
Quote: Japan Meteorological Agency Upper-air observation by
Altitude
Hi
Low
①
②
Low
Hi
Pressure
Observed temperature
Observed temperature
dry adiabatic line
stable atmospheric conditions
unstable atmospheric conditions
low temperature high

⑰ Geopotential altitude Isolines
You can display isolines of atmospheric pressure, geopotential altitude, temperature, and freezing level separately from layers.
An isoline is a line that connects points with the same weather conditions.
If you click on the geopotential height, the isoline of the geopotential height will be displayed. However, it is
currently PC version only.
After clicking the Geopotential heights you have to adjust the Altitude slider to 500 or 850hPa.
Geopotential altitude is the height calculated using
the observed pressure, temperature, and humidity.
At atmospheric pressure 850hpa
The theoretical altitude is 1500m, but if the
atmospheric pressure is low, the geopotential
altitude will be low, and if the atmospheric
pressure is high, the geopotential altitude will be
high.
PC version geopotential altitude
The theoretical altitude： 1500m

⑱Temperature isolines
If you click on the temperature, the temperature isolines (isothermal lines) will be displayed,
but currently only for the PC version.
PC version temperature isolines
Isotherms:
A line connecting points of equal temperature on a weather map.
By drawing isotherms on a map, warm and cool areas become clearer,
and changes in the isotherms over time make it possible to know
the movement of warm and cold air masses.

⑲ Freezing altitude isoline
Freezing altitude: Isolines display the altitude at which the temperature is 0°C (freezing point of water).If you click on the
freezing level, Isolines of the freezing level will be displayed, but currently only for the PC version.
PC版
Freezing altitude:
Freezing altitude is the altitude at which water freezes.
It is a factor closely related to the generation of dry snow (powder snow)
, wet snow, and ice, which are types of snow quality.
If the temperature stays below 0 degrees all day long, the snow will not
melt and will remain dry.
If the daytime temperature is 5°C and the nighttime temperature is
-5°C, the snow will melt during the day and the melted snow will
freeze solid at night, creating an ice burn.
Freezing level is closely related to snow quality.

Windy.com Mountain Climbing Utilization Edition
Check the weather, wind, temperature and rain in advance using the free weather forecast app "WINDY" and enjoy safe
and enjoyable mountain climbing.
① Windy.com Mountain weather check
② Climbing sensible temperature wind chill
③ Climbing rain forecast and countermeasures
④ Climbing fog, gas forecast and countermeasures
⑤ Climbing Thunder forecast and countermeasures
⑥ Climbing whiteout forecast and countermeasures
⑦ Climbing UV forecast and countermeasures

１．Windy.com Mountain weather check
Surface weather
forecast
②If you want to know the
wind and temperature at
the summit, adjust the
altitude slider and check.
③In the case of layered
wind, the wind speed at an
altitude of 1500m is
displayed in the weather
picker.
④Layer temperature
The temperature at an altitude of
1500m is displayed in the weather
picker.
weather
pickerTemperature 6℃
altitude slider
the wind speed
9m/s
Note that when you check the mountain weather on Windy.com, the weather forecast for the ground at zero altitude
is displayed in the initial state. When you want to know the wind and temperature at the summit,
adjust the altitude slider and display the weather picker to display the wind and temperature at that altitude.
Conversely, other layers cannot be confirmed for each altitude.
① Normally, the weather
forecast for the ground surface
(altitude zero) is displayed.

By default, the wind speed on the ground is displayed, so when climbing, you can adjust the altitude slider
under the layer menu to the altitude of the mountaintop to display the wind speed in the sky such as 900m,
1500m, 2000m, 3000m, 5500m. Is possible.
The altitude slider is visible when wind, temperature, and humidity layers are visible, and is not supported
for other layers.
Wind ground surface
Altitude setting
Wind Altitude 1500ｍ

Temperature defaults to surface weather information, typically the temperature drops by 0.6°C every 100 meters.
If you adjust the altitude slider in Windy to match the altitude of the mountaintop, the temperature will be
displayed at that altitude.
Surface temperature Altitude 1500m Temperature

２．Climbing sensible temperature wind chill
The temperature you feel in your daily life, the so-called sensible temperature, may differ greatly from what
the meteorological observatory reports, and wind speed is a major factor that affects the sensible
temperature.
Simply put, it feels like the temperature drops by 1 degree per 1 meter of wind speed.
Even if the temperature is 0°C, the sensible temperature is minus 10°C under a wind of 10 meters.
Choosing what to wear in the mountains is a matter of life and death.
Many of the mountain distress accidents were due to lack of preparation, as they were unable to move due to
hypothermia because they did not have warm clothes.
In the mountains, you should think about the worst possible situation, and clothing selection is fundamental.
The table below is a sensible temperature index calculated from the temperature and wind speed used in the
North American continent and serves as a guideline for knowing the degree of risk of frostbite outdoors.
In the case of exposed bare skin, if the sensible temperature index falls below -28°C, frostbite may occur
within 10 to 30 minutes.
When checking the temperature at the top of the mountain with Windy, consider the sensible temperature
index calculated from the wind speed, prepare clothes, and try to climb safely and enjoyably.

Sensory temperature index
Sensory temperature index quick reference chart
引用：よくわかる山の天気平井史生著
temperature
HIｇｈ Low
Wind
Speed
stong
weak
Reference: From the calculation formula of Environment Canada
Wind chill is information used in weather forecasts in the United States and Canada.Fromthe
calculation formula of Environment is information used in weather forecasts in the United
States and Canada.

３．Climbing Rain forecast and measures
Climbing on rainy days has the potential to lead to accidents and serious injuries.
Hypothermia can occur, for example, when the skin and clothes get wet with rainwater.
When climbing, be sure to pack your rainwear in your backpack.Also, swamps and rivers are swollen, visibility is bad, and
it is dangerous.
The mountain trail is dimly lit with the sunlight blocked, and sometimes you may get lost because you don't know where
you are walking.
Before climbing, check weather information such as Windy to see if there is an approaching cyclone, tropical cyclone,
typhoon, or cold front.
It is also possible to check the occurrence of clouds in the mountains using the "Meteogram" function of Windy, which is
helpful.
"Meteogram"

＊At ground level it is 1013hPa (1 atmosphere), and as the altitude increases
by 1000m, the atmospheric pressure decreases by about 100hPa.At the
summit of Mt. McKinley (6190m), the atmospheric pressure is about 394hPa.
Windy Meteogram
You can see the clouds at different altitudes.
Cloud/Rain:
Clouds are displayed in gray, darker clouds are displayed in
black. You can see the height of the clouds.
Rain:
Regular rain is shown in blue.
Convective rainfall:
It is rain that falls in an unstable atmosphere, and is displayed
in purple. It is a short, strong rainfall that may be accompanied
by thunder, so be careful when climbing.
Snow：
Snowfall, shown in light blue. A useful index for winter
mountaineering.
Flight Level (FL) is one of the flight altitudes used in
aviation."FL" followed by a number in units of 100 feet.
Rain Snow

４．Mountain climbing Fog, gas forecast and measures
There are places where fog is likely to occur due to topographical surfaces and natural conditions.
As the temperature rises, the air near the ground cools and the morning fog disappears.
Fog is a state in which water droplets and moist particles that are smaller than raindrops are floating, so
when you are in the fog for a long time, wear rain gear to keep your clothes dry.
Also, be careful as the stones and rocks on the mountain trail are wet and slippery.
"When you are covered in fog, it is necessary to remember how to use the GPS and compass and how to
read topographical maps in order to avoid getting lost."
In Windy, there is a fog item in the layer, and you can see
the occurrence of fog with black and white densities,
but please note that the weather conditions at the top of
the mountain are different because it is information on
the ground surface (altitude zero).
Indication of fog formation in
black and white shades

５．Climbing Thunder forecast and measures
Before climbing, check weather information such as Windy to see if low pressure, tropical cyclones, typhoons and
cold fronts are approaching.
In Windy, you can check the forecast in the layer “Thunderstorm”.
Defined as the number of flashes of light in an area of 1 square kilometer in a day, the unit used to express the intensity
of a ``thunderstorm‘’ is ``l/km2‘’.
l is the average total lightning density. The name of ECMWF is Averaged total lightning flash density in the last 3 hours
Abbreviation is litota3
The ECMWF description shows the total lightning flash rate averaged over the last 3 hours.Having units of flashes per
square kilometer per day, it is easier to understand by converting to units of flashes per 100 km2 per hour.

Thunderstorm：
The occurrence and frequency of lightning are displayed in color.
The higher the number, the higher the probability of lightning occurrence.
(the more the color becomes red or purple)

The layer CAPE index (convective effective potential energy) is also useful for lightning forecasts.Stable up to 1000.
Values from 1000 to 2000 can indicate forming of moderate thunderstorms, and over 2000 severe ones.
自由対流高度(LFC)
中立高度(LNB)
LNB:
Level of Neutral Buoyancy The altitude above which a parcel of air cannot rise on its own.
anvil cloud
Convective available potential energy
Level of free convection (LFC) LFC: Afterwards, it rises by itself
Lifted Freeze Altitude (early cloud)
Rising air current vs convection suppression

６．Climbing whiteout forecast and measures
One thing to watch out for when climbing mountains in winter is the whiteout, which can make visibility extremely poor due to
snowstorms. There are many victims every year by deviating from the route.
In whiteout, the boundary between the snow surface and the sky is lost, creating the illusion of floating in a white space. You will not be
able to move, and the blowing snowstorm will drain your health.
If you step on a snow cornice by mistake, you may slide down, and eventually you will not be able to move, and you may end up doing
nothing.
The basic countermeasure is to secure a place that can withstand the blizzard or create a snow cave and wait until the weather calms
down.
Please check the visibility situation in advance with Windy's layer visibility (visibility) before climbing.
visibility ：5.2㎞

７．Climbing UV protection
In the case of high mountains, the air layer through which ultraviolet rays pass is shorter than on the ground, so the
ultraviolet rays are stronger than on the ground.
An increase in altitude of 1000m increases UV radiation by about 10%.Also, during the remaining snow season, you need to
be careful of the reflection of the snow on the ground.UV rays are invisible. In mountains with low temperatures, you may
be exposed to strong UV rays without realizing it.Even if the sky is cloudy, 60 to 80% of the UV rays on a sunny day are
pouring down.
You can check the UV forecast in the weather information before climbing, and you can check it with the layer UV index
(ultraviolet index) in Windy.
The UV index (ultraviolet index) is an index designated by the World Health Organization to clearly indicate the degree of
influence of ultraviolet rays on the human body.

8.Layer Outdoor map
It can be used as a hiking map using Open Street Map.
Open Street Map also displays mountain trails and hiking routes in an easy-to-understand manner.
【Google Map】【OpenStreetMap】
mountain trail, hiking route
＊OpenStreetMap：
OpenStreetMap is a collaborative project to
create a freely available and editable world map.
Mountain trails
and hiking routes
are not displayed

Windy.com Utilization of fishing
Absolutely recommended for fishing! Free weather forecast app "WINDY" Wind speed, waves, seawater
temperature, temperature, weather, ocean currents, tidal currents

１．Seawater temperature and fish activity
If the seawater temperature becomes too low, the activity of fish will generally decrease. If the activity drops, even if you
drop the bait in front of the fish, it will not bite, so the fishing results will be difficult. The minimum seawater temperature is
15°C or more, and the optimum seawater temperature is about 23-27°C.
Seawater is said to be difficult to cool down once it warms up instead of being difficult to heat due to its nature.
Sea water is difficult to heat, so it is said that the water temperature rises about a month later than the season
on the ground.
In the Northern Hemisphere, seawater temperatures begin to drop gradually towards the end of the year, with
the coldest season from late February to March.
The activity of fish changes greatly depending on the seawater temperature, which greatly affects the fishing
results.
The reason is that the lower the water temperature, the higher the saturated dissolved oxygen content, and the
higher the water temperature, the lower the saturated dissolved oxygen content. Fish that take in oxygen from
the water and breathe through their gills become oxygen deficient when the water temperature rises and the
amount of oxygen decreases, making it impossible to perform normal predatory activities.

Fish species Suitable water
temperature
Note
Japanese sea perch 14～25℃ 15℃ or less, move to deep field
Japanese black porgy 15～21℃ If the water temperature drops by 2-3°C or more, the activity
decreases.
Japanese horse mackerel 16～26℃ At water temperatures below 15°C, they move to deep water and
offshore.
black rockfish 12～16℃ In the summer when the water temperature rises, they move to deeper
water.
flounder 15～25℃ Even if the water temperature is as low as 10℃ or less, if there are
young fish, you can expect good fishing results.
bigfin reef squid 18～23℃ It is most active when the water temperature is around 20°C, which is
easy to target even in shallow water.
Hong Kong grouper 15～25℃ Activity decreases at water temperatures below 15°C
amberfish 16～21℃
Suitable water temperature for fish

Check seawater temperature
Estimated sea surface temperature at the actual time. For locations close to the coastline, the actual values are affected by
the coastline, seabed shape, wind and waves.
However, near the surface of the sea, there is a layer with little change in
water temperature in the depth direction, a surface mixed layer.
In the case of Japan, the seawater near the sea surface is warmed by
solar radiation in the summer, and the temperature difference between
the sea surface and the lower layer becomes large, so the surface mixed
layer becomes thinner.
In winter, seawater is cooled on the surface of the sea, and wind blowing
over the sea actively stirs the water in the upper and lower layers, forming
a thick surface mixed layer.

２．Fishing-Find back wind!
A big problem in fishing is the headwind.
No matter how much you swing the rod, the lure will not fly. Therefore, when looking for a place where the wind is
weak even a little, use Windy to search for the back of the wind.
For example, the point in the left image below has a wind speed of 5 m/s, but if you click the white point ○ on the
opposite side of the island and move it, you can find a weak wind point with a wind speed of 3 m/s.

３．Fishing Search for waves and swells!
In order to enjoy fishing safely, it is essential to know information about waves and swells.
For example, the point in the image below is a wave with an interval of 1.4m (period: 7S) to the southeast,
which is not suitable for fishing on the beach, and should be avoided.

What are waves？
Waves are a combination of waves generated directly by the wind (wind waves) and gently rounded waves (swells)
caused by wind waves generated in distant places.
There are two types of waves: wind waves and swells. Waves are affected by topography.
①wind waves: Waves caused by the wind
②Swells:Waves propagated by wind-generated waves in other sea areas are called swells.
Typical examples of swell include waves caused by the aftermath of storms.
Swells have a longer period and longer wavelength than wind waves.
wind
waves
Swells

Wave heights up to 1m are safe for fishing.
Most parts of the shore may be covered with waves when it exceeds 1m.
Fishing and wave height guideline
Meter（ｍ） Feet(ft)
Height of parts of
body
State of sea
0.3048 ０ft flat calm
0.6096 １ft shin Fishing OK
0.9144 ２ft knee to thigh fishing with caution
1.2192 ３ft waist〜belly fishing difficult
1.524 ４ft chest〜shoulder Danger of fishing
1.8288 ５ft〜 Head
Danger of fishing
Shin
Knee
Waist
belly
Chest
Shoulder
Head

The interval between normal sea swells is about 3 seconds.A wave with a period of 6 seconds or less is a wind wave.For longer
periods, the speed of the waves increases, the amount of moving water increases, and the power increases.
8 seconds or more is a dangerous level, move to a safe place.If the interval between swells (wave period) is long, the beach will
be rough and it will be difficult to get out of the kayak.Also, even if you fish from the shore, the bottom will be rough and you
will not be able to catch it.
Guide to fishing and wave cycles
swell cycle Note
3 seconds or less choppy waves clam
４〜５ seconds
wind wave
There is a little swell. Fishing from tetras is dangerous
６〜７ seconds
It is quite undulating. It's okay if it's a high scaffolding embankment.
８ seconds less It's pretty rough. Move to a place in the bay where the waves are calm
For example, if the wave height is 0.7m and the swell interval (wave period) is 8 seconds, a wave of about 0.7m will come every 8
seconds.8 seconds between swells (wave cycle) is a dangerous number.
Due to the amplification of the power of the swell that entered the shallow waters of the coast, there is a possibility that the waves
will sometimes reach twice the average value.

Fishing and Significant Wave Height
Wave heights used in weather forecasts are usually expressed as significant wave heights.Significant wave height is the average
value of the top 1/3 of all wave heights arranged in descending order, which is close to the wave height that people intuitively
perceive.
However, even with this convenient "significant wave height", larger and smaller waves are generated.For example, 1 wave in
10 waves is 1.3 times the significant wave height, 1 wave in 100 waves is 1.6 times the significant wave height, and 1 wave in
1000 waves is twice the significant wave height.
In addition, one wave in thousands or tens of thousands of waves may be several times the significant wave height, and this is
called a big wave.In this way, waves with high heights that occur stochastically, even though they are small in proportion to the
whole, are called big waves.When fishing at sea, you have to be careful of big waves that come once in tens of thousands of
times.
1 wave in 100 waves is 1.6 times
the significant wave height倍
the significant wave height ２ｍ
Average value of 1/3 from
the largest wave height significant wave height
Sort in descending
order of wave
height
Wave height observed
at a point

４．Fishing - Onshore, Offshore
オフショアオンショア
Offshore (wind that blows from the shore toward the sea)
conditions are good and the waves are good.
Onshore (wind that blows from the sea toward the shore)
conditions It becomes a turbulent, jumbled wave.
If you plan to go beach fishing, check the wind direction on Windy.com to make sure the wind
direction is offshore and suitable for fishing.
You can cast a lure offshore, but you can't cast a lure onshore because of the headwind.
Offshore On shore
The wind dampens the
power of the waves.
Swell
Swell

If you want to check the wind force, wind direction, wave height, wave period, and wave direction on Windy.com,
follow the steps below to display the wind direction, strength, wave direction, and strength for each point.
５．Check wind force, wind direction, wave height, wave period, wave direction
Select the layer wave, display the weather
picker of the point, and click the orange part.
Wind force, wind direction, wave height, wave period and
wave direction are displayed.

When you select a time and slide it, the wind direction, strength, wave direction, and strength of
the time you want to check are displayed in chronological order so that you can see it visually.
Forecast after 8 hours
Slide

７．Fishing - tidal currents, ocean currents
There are tidal currents and ocean currents as major currents in the sea.
Currents that flow in a certain direction are called ocean currents. A tidal current is the flow of seawater created by the ebb
and flow of the tide, and refers to the flow of seawater that changes about 180 degrees between high tide and low tide.
The most relevant data for land fishing and breakwater fishing is the tidal current data.
The notation of Windy.com makes it much easier to understand the "flow direction" when viewed on a computer, and it is
difficult to understand on a tablet or smartphone.
tidal currents ocean currents

Movement of the tide
If you go fishing on the breakwater, the current will change due to the influence of the topography.
When casting floats, baits, and lures, consider the movement of the tide when casting.
tidal currents
Breakwaters have a
large impact on tidal
currents
The tidal current changes greatly in
the bay
Watch out for
changes in the
breakwater
Hit
Faster in tight spaces
Great change
even at the cape
No change
without
obstacles

Windy.com Surfing
Absolutely recommended for surfers!
Free weather app "WINDY" wind speed, waves, water temperature, temperature, weather

What are waves, swells, swells 2, swells 3, wind waves at Windy.com?
The definitions of waves, swells, swells 2, swells 3, and wind waves in the weather layer items of Windy.com are as follows.
Waves: Significant wave height and its period of all wave types combined (swell and wind waves). Close to the shoreline, the
actual height is influenced by the shape of the sea bottom.
Swell1: A swell consists of wind-generated mechanical waves that are not significantly affected by the local wind at that time. They
have been generated elsewhere and some time ago, usually travelling long distances.
Swell2: Secondary swell is produced also by winds far away but in other places than Swell1. It has different heights, directions and
periods than Swell1.
Swell3: Another secondary swell, with different heights, directions and periods than Swell1 and Swell2. More detailed info about
the swells is here.
Wind waves: Wind waves, or wind-generated waves, are surface waves that occur on the free surface of bodies of water (like
oceans, seas, lakes, etc.). They result from the wind blowing over an area of water surface. Wind waves are generated by the
immediate local wind – which gives them the direction. After the wind ceases to blow, wind waves are called swells.
引用先：Description of weather overlays

Waves are a combination of wind
waves, swells, and topographical
influences.
Swell 1 is a swell caused by waves
generated in the distance.
Swell 2 is a swell caused by a distant
wave different from swell 1.
Wind waves are caused directly by
the wind
Windy.com Examples of waves, swells, swells 2, swells 3, wind waves

Basically, all you have to do is look at the "waves" on the layer.
Check the size and direction of the waves while being conscious of what size
and angle they are entering the surf point.
We believe that the influence of swells will change depending on the
environment such as the location of the surf point, direction, and topography.
Therefore, "swell 2" may be helpful at one point, and "swell 1" may be helpful
at another point.
Direction, height and
spacing of waves
Wave height color
graph

The wave height is around 1m, which is the best size for beginners to practice, around 1.5m is a
very good size for intermediate players, and around 1.8m is for advanced players.
Surfing and wave height guideline
meters（ｍ） feet(ft) Body part heigh Surfing skill
0.3048 ０ft
0.6096 １ft Shin beginner
0.9144 ２ft knee to thigh beginner
1.2192 ３ft waist to belly Beginner intermediate
1.524 ４ft chest to shoulder intermediate
1.8288 ５ft〜 Head Intermediate advanced
3.048 ６ft〜 Over Head advanced
4.572 １０ft〜 double advanced
0.3048 １５ft〜 triple advanced

The interval between sea waves in normal times is about 3 seconds.
With this numerical value, it is not a swell but a wind wave, and the wave period is wind wave up to 6 seconds.
If the wave period is 6 seconds or more, the wave is suitable for surfing. As the wave period increases, the speed of the
wave increases, so the power also increases. When the wave period exceeds 10 seconds, it is well worth a wave check,
even if the wave height is low.
Surfing and Wave Cycle Guide
Wave period Note
6 seconds or less, jumbled waves
It is a newly born weak swell that is not suitable for surfing.Areas with
forecasts in this range have rough seas and strong onshore winds.
7-9 seconds wind waves, uneven waves Wind wave range.Not the best waves, but surfable enough
10-12 seconds good waves
A swell generated in a place some distance away due to strong winds.There
is energy that can reach far away.
13-15 seconds Typhoon waves
Ground swell A swell usually caused by a storm that is fairly far away.
Typhoon swells and swells that bring good waves to Indonesia are also in
this range. It is a swell suitable for surfing, and when it comes to a shallow
area, the energy of the wave concentrates and the wave that actually
collapses tends to be larger than the height of the swell.

Surfing and Significant Wave Height
Wave heights used in weather forecasts are usually expressed as significant wave heights.Significant wave height is the average
value of the top 1/3 of all wave heights arranged in descending order, which is close to the wave height that people intuitively
perceive.
However, even with this convenient "significant wave height", larger and smaller waves are generated.For example, 1 wave in
10 waves is 1.3 times the significant wave height, 1 wave in 100 waves is 1.6 times the significant wave height, and 1 wave in
1000 waves is twice the significant wave height.
In addition, one wave in thousands or tens of thousands of waves may be several times the significant wave height, and this is
called a big wave.In this way, waves with high heights that occur stochastically, even though they are small in proportion to the
whole, are called big waves. Therefore, when surfing, even if the waves are small, there is a possibility that you can meet a big
wave about once in half a day.
1 wave in 100 waves is 1.6 times
the significant wave height倍
the significant wave height ２ｍ
Average value of 1/3 from
the largest wave height significant wave height
Sort in descending
order of wave
height
Wave height observed
at a point

Surfing and Shallow Water Effect
The shallow sea effect is "a phenomenon in which wave height, wave speed, and wavelength change due to the influence of the
seabed when waves enter shallow sea areas (shallow sea areas), causing refraction and wave breaking.“
When a wave from offshore enters a shallow water area, if the water depth becomes shallower than 1/2 of the wavelength, the
wave height, wave speed, and wavelength will change due to the influence of the seabed.In sea areas where the water depth is
1/2 to 1/6 of the wavelength, the shallower the wave height, the lower the wave height, which is about 90% of the original wave
height. However, when the water depth becomes shallower than that, the trend reverses and the wave height rises rapidly.Also,
the wave speed tends to decrease as the water depth becomes shallower, and the wavelength tends to become shorter.
"Swell" has a longer wavelength and period than "Wind wave", so it has the property that the wave tends to rise due to the
shallow sea effect.Therefore, swells coming from offshore can suddenly become high waves near the coast, and accidents
involving waves can occur, so caution is required. coastal current shore wave
swell change point
Water depth 50m
Reciprocating motion
Water depth 5m

Surfing- Onshore, Offshore
オフショアオンショア
Offshore (wind that blows from the shore toward the sea)
conditions are good and the waves are good.
Onshore (wind that blows from the sea toward the shore)
conditions It becomes a turbulent, jumbled wave.
If you plan to go beach Surfing, check the wind direction on Windy.com to make sure the wind
direction is offshore and suitable for Surfing.
Offshore On shore
The wind dampens the
power of the waves.
Swell
Swell

Surfing- Check seawater temperature
Estimated sea surface temperature at the actual time. For locations close to the coastline, the actual values are affected by
the coastline, seabed shape, wind and waves.
Before surfing, use Windy.com to check the water temperature and choose the best wetsuit.
However, near the surface of the sea, there is a layer with little change in
water temperature in the depth direction, a surface mixed layer.
In the case of Japan, the seawater near the sea surface is warmed by
solar radiation in the summer, and the temperature difference between
the sea surface and the lower layer becomes large, so the surface mixed
layer becomes thinner.
In winter, seawater is cooled on the surface of the sea, and wind blowing
over the sea actively stirs the water in the upper and lower layers, forming
a thick surface mixed layer.

Seawater temperatures and suitable wetsuits for comfortable surfing are as follows.
Surfing Sea water temperature and wet suit
Seawater
temperatures
temperature suitable wetsuits Note
2～15℃ －5～15℃ Dry Suit
15～20℃ 14～20℃ Fill suit
18～24℃ 17～25℃ S/S STEAMER
18～26℃ 23～30℃ spring

Windy.com Diving Utilization Edition
Absolutely recommended for diving! Free weather forecast app " Windy" Predict wind speed, waves, seawater
temperature, temperature, weather, ocean currents, and tides
Introducing safety measures against waves and swells during diving.

１．Entry & Exit
When entering or exiting a place with waves and swells, it is basic to aim for the timing when the waves are small.
The surf zone is especially strong, so try to get out of it as quickly as possible.
Also, in the case of boat diving, when entering and exiting, leave the boat immediately so as not to hit the boat with the swell.
Before entering, check the weather information for the day with the weather layer items of Windy.com, swell, swell 2, swell 3,
wind wave, and try to dive safely! !
beach diving entry Board diving entry

How to use Windy.com　Basic.pdf

How to use Windy.com　Basic.pdf

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