The rainfall is unevenly distributed in India. Many regional variations are found in the distribution of annual rainfall. The distribution of annual rainfall shows two main trends:
- From the coastal areas, the rainfall decreases towards the west and North-West.
- The rainfall decreases towards the interior of the country.
The main factors controlling this distribution of rainfall are the presence of high mountains and the distance from the sea. The coastal areas get high rainfall. The west coast gets more than 200 cms. of rainfall while the east coast gets about 100 cms. of rainfall. The rainfall in the interior of peninsular India is as low as 50 cms. The Western Ghats, the Garo-Khasi hills, and the Sub-Himalayan region get more than 200 cms. of rainfall. But Rajasthan is dry as there is no high mountain to check S.W. Monsoons.
Distribution of Rainfall, The average annual rainfall of India is 118 cms. Regional variations in the distribution are found due to differences in relief of the country. Rainfall is unevenly distributed throughout the country.
India can be divided into the following, rainfall regions:
- Areas of Heavy Rainfall: These areas get more than 200 cms. of annual rainfall. These include Western Coast and Western Ghats, Sub-Himalayas and the N.E. parts of India.
- Areas of Moderate Rainfall: These areas get annual rainfall of 100-200 cms. These include West Bengal, Orissa, Bihar, Eastern parts of U.P. and Madhya Pradesh and coastal plains of Tamilnadu.
- Areas of Low Rainfall: These areas experience an annual rainfall of 50-100 cms. These include Uttranchal, Haryana, Punjab, Gujarat, Peninsular plateau and Eastern Rajasthan.
- Areas of Scanty Rainfall: These areas get less than 50 cms. of annual rainfall. These include Ladakh, S.W. Punjab, Southern Haryana, Western Rajasthan, Kutch and Thar Desert.
