Climate refers to the sum total of weather conditions and variations over a large
area for a long period of time.
It refers to state of atmosphere over an area at any point of time.
The elements of weather and climate are temperature, atmospheric pressure,
wind, humidity and precipitation.
The climate of India is monsoon type.
•Monsoon is derived from „mausim‟which means season and it refers to the
seasonal reversal in the wind direction during a year.
•In Asia, this type of climate is found mainly in south and south-east.
DIFFERENCES IN INDIAN CLIMATE
In summer the temperature of Rajasthan is about 50‟C but in Jammu & Kashmir
In winter at J&K the temperature is -45‟C but in Thiruvanantapuram its 22‟C.
While precipitation is in the form of snowfall in upper parts of Himalyas, it rains
over the rest of country.
Most parts receive rainfall from June to July but some like Tamil Nadu receive it
even in the season of October and November.
The major controls of climate are:
1.Latitude : Due to curvature the amount of solar energy received varies according
2.Altitude: As we go higher there is a decrease in temperature of 16‟
3.Pressure and Wind system: As per latitude and altitude temperature and rainfall
also influences the climate.
4.Distance from sea: The sea exerts moderating influence on climate, regions near
sea experiences moderate climate.
5.Ocean Currents: It leads continentality which means very hot during summers
and very cold during winters.
FACTORS AFFECTING INDIAN CLIMATE
Tropic of cancer almost divides the country in two equal parts running from Rann
of Kuchh to Mizoram.
The region lying in the south of tropic of cancer is tropical whereas the region in
north is in sub tropical.
Therefore India receives both tropical as well as sub-tropical climate.
India has mountains in north with average height of 6000m and coast line of about
The Himalyas act as a barrier to enter winds in India from Centeral Asia.
That‟s why it experiences mild winters as compare to Centeral Asia.
3.PRESSURE and WINDS
It is further devided in three parts.
•Pressure and surface winds
•Upper air circulation
Pressure and surface winds: India lies in the region of north-easterly winds which
originate from northern hemispher and blow towards south but
deflected to right due to corollis force.These winds carry small silts that‟s why
don‟t affect India‟s rain.
4.Upper air circulation: Winds travel from a low pressure area to high
pressure area. Air moves from indian ocean to south-east direction crossing
equator and turns right towards indian subcountinent giving rain to it. The upper
air circulation over warm oceans is called jet stream.
5.Western disturbances: During the time of winters in India cyclone formation
takes place in „mediterranean sea‟whose winds are very powerful that after
crossing Pakistan, Afghanistan they finally reach jammu and kashmir leads to
rainfall in winters there.
The unifying influence of the monsoon on the Indian subcontinent is quite
The seasonal alteration of the wind systems and the associated weather conditions
provide a rhythmic cycle of seasons.
Even the uncertainties of rain and uneven distribution are very much typical of the
The Indian landscape, its animal and plant life, the people, including their
festivities, revolve around this phenomenon.
Year after year, people of India from north to south and from east to west, eagerly
await the arrival of the monsoon.
These monsoon winds bind the whole country by providing water to set the
agricultural activities in motion. The river valleys which carry this water also unite
as a single river valley unit.
Early in the season, the windward side of the Western Ghats receives very heavy
rainfall, more than 250cm.
The Deccan Plateau and parts of Madhya Pradesh also receive some amount of
rain in spite of lying in the rain shadow area.
The maximum rainfall of this season is received in the north-eastern part of the
Rainfall in the Ganga valley decreases from the east to the west. Rajasthan and
parts of Gujarat get scanty rainfall.
The breaks in the monsoon are related to the movement of the monsoon tough.
The trough and its axis keep on moving northward or southward. When the axis of
the monsoon trough lies over the plains and widespread rain occur in the
Mawsynram in the southern ranges of the Khasi Hills receives the highest average
rainfall in the world.
Ques. Why is monsoon known for its “uncertainties”?
While it causes heavy floods in one part, it may be responsible for droughts in the
It is often irregular in its arrival and its retreat. Hence, it sometimes disturbs the
farming schedule of millions of farmers all over the country.
During October-November, the monsoon trough or the low pressure trough over
the northern plains becomes weaker. This is gradually replaced by a high-pressure
The south-east monsoon winds weaken and start withdrawing gradually. By the
beginning of the October, the monsoon withdraws from the Northern Plains.
The months of October-November form a period of transition from hot rainy
season to dry winter conditions. The retreat of the monsoon is marked by clear
skies and rise in temperature.
While day temperatures are high, nights are cool and pleasant.
Owing to the conditions of high temperature and humidity, the weather becomes
rather oppressive during the day. This is known as “OCTOBER HEAT”.
The low-pressure conditions, over north-western India, get transferred to the Bay
of Bengal by early November.
This shift is associated with the occurrence of cyclonic depressions, which
originates over the Andaman Sea.
These cyclones generally cross the eastern coasts of India cause heavy and
These tropical cyclones are often very destructive.
The thickly populated deltas of the Godavari, the Krishna and the Kaveri are
frequently struck by cyclones, which cause great damage to life and property.
The monsoon type of climate is characterised by a distinct seasonal pattern.
The weather conditions greatly change from one season to the other. The coastal
areas do not experience much variation in temperature though there is variation
in rainfall pattern. Four main seasons can be identified in India- the cold weather
season, hot weather season, the advancing monsoon and the retreating monsoon
with some regional variations.
THE COLD WEATHER SEASON (WINTER)
1. The cold weather season begins from mid- November in northern India and
2. December and January are the coldest months in the northern part of India.
3. The temperature decreases from south to the north.
4. Days are warm and nights are cold.
5. Frost is common in the north and the higher slopes of Himalayas experience
6. The northeast trade winds blow from land to sea and hence, for most part of the
country, it is a dry season.
7. Some amount of rainfall occurs on the Tamil Nadu coast from these winds as,
here they blow from sea to land.
8. The weather is normally marked by clear sky, low temperatures and low
and feeble variable winds.
9. A characteristic feature of the cold weather season over the northern plains is a
the inflow of cyclonic disturbances from the west and the northwest.
10.They cause the much- needed winter rains over the plains and snowfall in the
11.Total amount of winter rainfall locally known as „mahawat‟ is small; they are
of . immense importance for the cultivation of „rabi‟ crops.
12. The peninsular region does not have well- defined cold season.
THE HOT WEATHER SEASON (SUMMER)
1. From March to May, it is hot weather season in India.
2. The influence of shifting of the heat belt can be seen clearly from temperature
recordings taken during March- May at different latitudes.
3. In peninsular India, temperature remain lower due to the moderating influence
4.The summer months experience rising temperature and falling air pressure in
northern part of the country.
5. Towards the end of May, an elongated low pressure area develops in the region
extending from the Thar Desert in the northwest to Patna and Chotanagpur
6. The striking feature of the hot weather season is the „loo‟. These are strong,
gusty, hot, dry winds blowing during the day over the north and northwestern
7. Dust storms are very common during the month of May in northern India. These
storms bring temporary relief as they lower the temperature and may bring light
and cool breeze.
8. In West Bengal, these storms are known as „Kaal Baisakhi‟.
9. Towards the close of the summer season, pre- monsoon showers are common
especially, in Kerala and Karnataka.
DISTRIBUTION OF RAINFALL
There are three types of rainfall :-Low rainfall (Less than 50 cm.)
- Average rainfall (Between 50 to 250 cm.)
- High rainfall (More than 250 cm.)
1. Parts of western coast and northern India receive over about 400 cm of rainfall
2. It is less than 60cm in western Rajasthan and adjoining parts of Gujarat,
3. Rainfall is equally low in the interior of Deccan plateau, and east of the
4. The rest of the country receives moderate rainfall. Snowfall is restricted to the
Because of the nature of monsoons, the annual rainfall is highly variable from year
to year. Variability is high in the regions of low rainfall such as parts of Rajasthan,
Gujarat and leeward (rain shadow area) side of the Western Ghats. While the
areas of high rainfall are responsible to be affected by the floods and the areas of
low rainfall are drought- prone.
SOME IMPORTANT TERMS
1. Frost- A state in freezing, frozen dew.
2. Loo- Strong, gusty, hot, dry winds blowing during the day over the north and
3. Mango showers- Pre-monsoon showers in Kerala and Karnataka help in
mangoes earlier, known as monsoon showers.
4. Trough- large vacuum in between of the Himalayas and the peninsular plateau,
5. Leeward- Rain shadow area.