This document summarizes various weather instruments used to measure temperature, humidity, wind speed, wind direction, air pressure, rainfall, sunshine, and cloud cover. It describes key features of instruments like thermometers, hygrometers, anemometers, wind vanes, barometers, rain gauges, sunshine recorders, and cloud mirrors. It also discusses the Stevenson screen, which houses other instruments to measure weather elements in a sheltered and shaded environment.

1. Weather Instruments
Geography

2. Temperature
• Max Min Thermometer
• Six’s Thermometer
– Max-Mercury
– Min-Alcohol
• Measures shade
temperature (Stevenson’s
screen)
• Read off at bottom of the
index (reset with magnet)
• Read at eye level
• Measured in ºC

3. Humidity
• Wet/Dry Bulb thermometer
• Hygrometer
– Wick and reservoir of water
• Comparison tables
1. Calculate depression of wet
bulb (Dry – Wet)
2. Read off table
• Measures in shade
(Stevenson’s screen)
• Units = % Relative humidity

4. Wind Speed
• Anemometer
– Cups or blades
– Clear unobstructed
location
• Km per hour

5. Wind Direction
• Wind Vane
• Recorded on Wind Rose
• Compass Directions

6. Air Pressure
• Aneoid Barometer
• Barograph
– Plots changes in pressure
• Millibars
• Measured in shade
(Stevenson’s screen)

7. Rainfall
• Rain gauge
• Siting factors
– Clear view of sky
– Recessed into ground
– Approx 30cm above
ground
– Grassy surface (avoid
splash back)
– Read off at eye level
• Regular intervals
(24hours)

8. Sunshine
• Sunshine recorder
– Burns a timeline
– Traces sun shine not
hours of daylight
• Glass ball focuses
light
• Burns line onto card
• Units = Hours

9. Stevenson’s Screen
• Houses temperature /
humidity /pressure
instruments
• Features
– Insulated roof
– Painted white to reflect
heat
– Louvered (slatted)
sides aid air circulation
– Located 1.25-2m
above ground

10. Cloud Cover
• Cloud Mirror
• Divide mirror into 16
equal squares
• Lay mirror on ground
with clear view of sky
• Estimate cover
• Units = Oktas