Rainfall distribution and southwest monsoon in India

From mid-June (Ashada), the weather starts changing all of a sudden. The sky is clouded by clouds and the southwest winds start moving. These winds are popularly known as “southwest monsoon” as they begin from the southwest. With the arrival of this monsoon, the temperature drops significantly, that is, the temperature starts decreasing. But there is a great increase in air, due to which unbearable humidity is experienced and discomfort becomes unbearable. At that time, the condition here becomes like equatorial region. Let us know through this post how the rainfall distribution in India happens and how the southwest monsoon contributes to the rainfall in India.
Monsoon in India
Monsoon in India

Southwest monsoon

From mid-June to first July, the whole of India comes under the influence of the south-west monsoon. Since the air load is the lowest in northwestern India, steam-laden winds from the sea move rapidly towards it. There is heavy rain with lightning and glow.

Type of Monsoon

The southwest monsoon can be divided into two parts –
  1. Arabian monsoon
  2. Monsoon of the Bay of Bengal
The reason for this division is the nature of the Indian peninsula.

Arabian monsoon

The Arabian Sea’s monsoon moves earlier and is more powerful, but its power decreases in crossing the Western Ghats. Most of its cloud falls there. Through the gate of Narmada, some winds enter the interior of the country and meet the winds coming from the Bay of Bengal in Chotanagpur.

Monsoon of the Bay of Bengal

The monsoon of the Bay of Bengal arrives slightly later than the Arabian Sea, but it rains in most parts of the country. First he reaches the Arakan coast and then passes through the hills of Assam. Due to the state of Himachal, this monsoon has to become southeastern in northern India. Then it has to reach the low-lying region in the north-west, so it is natural for the monsoon to turn towards the west. From this monsoon, the rainfall decreases gradually towards the west.

Delivery of monsoon

The average rainfall in India is around 300–650 millimeters (11.8–25.6 in), but its distribution (volume and duration) clearly affects the position and natural texture.
Rainfall is more in the hilly parts and on the windward side. Most percent (80%) of India’s total year is in June, July, August and September (from Asadh to Ashwin). This is the rainy season or rainy season of India.
The month of October is also kept under the rainy season. This is such a month in which neither the rain ends at all nor winter begins.


  1. Most of the rainfall occurs from June to September and 2/3 of the year remains dry. In addition to summer in Tamil Nadu, there is good rainfall in winter.
  2. Most of the rainfall comes from the monsoon winds.
  3. The distribution of rainfall is not uniform everywhere. Like in India Cherrapunji annual rainfall is 425 ″ and in Bikaner it is only 11 ″.
  4. The rain is torrential. Cyclonic rainfall is nominal.
  5. There can be uncertainty in the amount of rainfall, that is, it may start or end in some place late or ahead of time and sometimes the rainfall may be more or less than necessary. For this reason, Indian agriculture has been said to gamble with the monsoon.

Rain department

India can be divided into two parts based on rainfall –
  1. Areas of fixed rainfall, under which Bengal, Assam and the west coast (Malawar and Konkan coast) can be taken.
  2. Areas of erratic rainfall, including Bihar, Jharkhand, Odisha, Uttar Pradesh, Madhya Pradesh, Punjab, Rajasthan, Maharashtra, Mysore, Andhra Pradesh and Tamil Nadu.

Four parts of India based on the amount of rainfall

  1. Areas of dense rain (where there is more than 80 ″ of rain) – This will cover the western coast, Asa and the southern slope of the eastern Himalayas.
  2. Areas of normal rainfall (where there is a rainfall from 40 ″ to 80 ″) – Eastern slope of Western Ghats, Eastern part of Tamil Nadu and Andhra Pradesh (Cormandal coast, West Bengal, Bihar, Orissa, Madhya Pradesh and eastern part of Uttar Pradesh). Will be included.
  3. Areas of low rainfall (where there is a rainfall from 20 ″ to 40 ″) are covered under most parts of Tamil Nadu and Andhra Pradesh, Mysore, eastern part of Maharashtra, Gujarat, eastern part of Rajasthan and most of western Punjab.
  4. Rainfed area (where there is less than 20 ″ rainfall) – It mainly consists of western part of Rajasthan and southern part of Punjab.