The compilation of these Climate Notes makes students exam preparation simpler and organised.
Climate of India
Did you ever hear your mother say, “The weather is getting hot” or your uncle says, “The climate of this area is cold”? Do you know what is the difference between Climate and Weather? Rest assured because you’ll find out what it is soon and study the Climate of India as well.
Climate and Weather
Climate is a total of weather conditions and variations over a large area for a very long period of time of more than thirty years. But how is weather different from climate? Weather refers to the state of the atmosphere over an area at any given period of time. Weather can change throughout the day whereas the climate of a country is the same for many years.
The Climate of India
The climate of India is described as a monsoon type. This type of climate is found in south and southeast Asia. However, there are variations in climatic conditions in the country itself. The coastal regions of India show the least amount of difference between the temperatures of night and day. In the interior regions, the difference in temperatures of day and night is huge.
Climatic controls are the factors that control the variations in temperature in the climate of India. There are six major climatic controls. They are:
Latitude: As the earth is round, sunlight does not reach everywhere equally. The temperature decreases as we move from the equator to the poles.
Altitude: As we move from the surface of the earth to the higher altitudes, the temperature decreases.
Pressure and wind system: The pressure and wind system of any area depend on the latitude and altitude of that place. Thus, it influences the temperature accordingly.
Distance from the sea: Coastal regions are cooler as compared to interior regions. As the distance from the sea increases, its influence decreases, and the people experience extreme weather conditions.
Ocean currents: Cold ocean currents flowing over a region will decrease the temperature of that area whereas warm currents will increase the temperature.
Relief features: Relief features are the barriers that block currents from entering the country. High mountains act as barriers for cold or hot winds.
Factors affecting the Climate of India
We know that the Tropic of Cancer, which separates the tropical areas and the sub-tropical areas of the earth, passes through the middle of Rann of Kuchchh in the west to Mizoram in the east. Therefore, the climate of India has characteristics of both tropical and sub-tropical climates.
India has very tall mountains of about 6000 meters. The Himalayas prevent the cold winds from central Asia from entering India. It is due to this reason that India has a milder winter as compared to central Asia.
Pressure and Winds
India has a unique wind and pressure conditions. During winter, the northern area near the Himalayas has high pressure. Therefore, winds from this region blow to the south where the pressure is lower. In summer, the northern part has lower pressure. Therefore, there is a reversal of wind direction. The winds from the south blow towards the north. These winds greatly affect the climate of India.
The Indian Monsoon
The climate of India depends greatly on monsoon winds. The monsoons usually happen due to the differential heating of land and water. You probably know that land heats faster than water. This change in heating leads to a difference in pressures, which in turn leads to currents. Thus, the changes in pressure conditions also affect the monsoons. Normally, there is high pressure in the tropical eastern-south Pacific Ocean and low pressure in the tropical eastern Indian Ocean. But as years have gone by, there has been a reversal in the pressure conditions. Therefore, the eastern Pacific has lower pressure. This periodic change in pressure conditions is known as Southern Oscillations or SO.
The climate of India has distinct seasonal patterns. The weather conditions change greatly from one season to another. The changes in temperature are extreme in the interior regions. The coastal regions do not experience extreme temperatures.
The Cold Weather Season (Winter)
The cold weather season in India begins from mid-November and stays until February. December and January are the coldest months. The temperature decreases as we go from south to north. The average temperature in the south in winter is 24° – 25° while in the north, it is between 10° and 15° Celsius.
The Hot Weather Season (Summer)
The hot weather season in India is from March to May. In May, the temperatures go up to 45° in the northwestern parts of the country. Towards the end of the summer season, there are pre-monsoons showers common in Kerala and Karnataka. They are often referred to as ‘mango showers‘ because they help in the early ripening of mangoes in these states.
The Advancing Monsoon (Rainy Season)
By early June, the trade winds of the southern winds bring abundant moisture to the country. The windward side of the Western Ghats receives very heavy rainfall, more than 250 cm. The monsoon is known for its uncertainties. While it causes heavy floods in one part, it may be responsible for droughts in the other. It is also irregular in arrival and retreat.
Retreating Monsoons (Transition Season)
During October-November, the monsoons become weaker. The sun moves towards the south. By the beginning of October, the monsoon withdraws from the Northern Plains. There is a transition from a hot rainy season to a dry winter season.
Distribution of Rainfall
Some parts of India receive about 400 cm of rainfall annually. However, it is less than 60 cm in Rajasthan and adjoining parts of Gujarat, Haryana, and Punjab. The rest of the country receives moderate rainfall. Owing to this nature of monsoons, the annual rainfall is highly variable from year to year.
Monsoons arrive in India approximately in:
a) early may
b) early June
c) early July
d) early August
b) early June.
By early June, the trade winds of the southern winds bring abundant moisture to the country. These winds precipitate to cause rainfall in the southern parts of India first.