Rainfall in India: Annual Rainfall, Distribution of Average Rainfall in India | UPSC Notes

By BYJU'S Exam Prep

Updated on: November 14th, 2023

Rainfall in India shows a great deal of variation. India is a fairly large country in terms of its physical area, and the climatic conditions vary greatly from region to region. The distribution of rainfall in India also reflects this. Some locations receive a lot of rain, while others just get a little. The yearly data from the Meteorological Department in 2022 show an average rainfall in India of 92.5 cm. The Average Annual Rainfall in India is roughly 115 inches (2900 mm). However, it varies greatly across the nation, falling as low as 50 inches (1270 mm) in the western Himalayan area and rising as high as 160 inches (4000 mm) in the northeast.

Rainfall plays a pivotal role in shaping the landscape and livelihoods of India, a country known for its diverse geography and climatic patterns. India experiences a range of rainfall patterns due to its vast size and varying topography, from the arid regions of Rajasthan to the lush green landscapes of the Western Ghats. Understanding the dynamics of rainfall in India is crucial for comprehending the country’s ecosystems, agricultural practices, and the daily lives of its people. The article discusses the Rainfall in India, along with the Average Rainfall, the distribution of Rainfall in India, and the patterns that affect the Rainfall distribution.

Rainfall in India

Rainfall in India is a crucial aspect of its climate, with significant implications for agriculture, water resources, and overall ecosystem balance. India experiences different types of rainfall, mainly characterized by the southwest monsoon and the northeast monsoon. The southwest monsoon, which occurs from June to September, brings the majority of the annual rainfall to most parts of the country. The northeast monsoon, on the other hand, affects the eastern coastal regions, particularly Tamil Nadu, during the months of October to December. These distinct rainfall patterns play a vital role in shaping India’s diverse landscapes and influencing the livelihoods of millions of people dependent on agriculture.

In addition to the southwest and northeast monsoons, other types of rainfall occur in specific regions. Orographic Rainfall occurs when moist air is forced to rise over mountain ranges, leading to enhanced rainfall on the windward side. Convectional Rainfall is common in areas with high temperatures, where the intense heating of the surface causes air to rise, condense, and form rain clouds. Cyclonic or frontal rainfall is associated with the movement of weather systems such as cyclones and depressions, resulting in widespread rainfall. These various types of rainfall contribute to the overall precipitation patterns in different parts of India, contributing to the country’s ecological diversity and agricultural productivity.

Types of Rainfall in India

The southwest monsoon and the northeast monsoon are the two major types of Rainfall in India. About 75% of Average Rainfall in India falls during the southwest monsoon, often known as the “long rains,” which span from June to September. The northeast monsoon, often known as the “brief rains,” which occur from October through December, contributes the remaining 25% of the total rainfall in India.

  • Southwest Monsoon: The interaction of two air masses- the warm, humid air mass over the Indian Ocean and the colder, dry air mass over Central Asia, leads to the southwest monsoon. Because of this interaction, a low-pressure area forms across the Indian subcontinent, which shifts the direction of the winds from the ocean to the land.
  • Northeast Monsoon: The northeast monsoon is brought on by the interplay of the warm Bay of Bengal air mass with the cold Siberian air mass. Depending on the region, India has a wide range of rainfall. The eastern coast, which includes locations like Kolkata and Odisha, receives considerably less rainfall than the western coast, which includes regions like Mumbai and Kerala. With more than 2000 mm of precipitation annually, the northeastern states, including Assam and Meghalaya- are the wettest in the nation.

Distribution of Rainfall in India

The Rainfall in India in 2022 was recorded at 92.5cm at the end of the monsoon season. The distribution of rainfall in India is as follows:

  • Extremely Heavy Precipitation regions: These areas receive more than 400 cm of rainfall annually. West Bengal, Odisha, Assam, Meghalaya, and Arunachal Pradesh are among them.
  • Very Heavy Precipitation regions: These are the areas that receive more than 250 cm of precipitation annually. These include Lakshadweep, Kerala, Tamil Nadu, and coastal Karnataka.
  • Heavy Precipitation regions: These areas receive more than 200 cm of rainfall annually. These comprise Meghalaya, Arunachal Pradesh, Mizoram, Nagaland, Manipur, Tripura, Sikkim, and Assam in addition to the Andaman and Nicobar Islands.
  • The Himalayan region: More than 200 cm of rainfall in this area each year. Parts of Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh are included in this.
  • Desert and Semi-desert regions: These are the areas that receive less than 50 cm of rainfall annually. These include Jammu and Kashmir, Rajasthan, Gujarat, and areas of Punjab and Haryana.
  • Coastal regions: These are the areas that get more than 100 cm of rain each year. These include Tamil Nadu, Kerala, Karnataka, and Andhra Pradesh.
  • Inland regions: These are the areas that get more than 150 cm of rain each year. These include Madhya Pradesh, Jharkhand, Chhattisgarh, and Maharashtra.

Average Rainfall in India

Every year, the Average Rainfall in India is around 125 cm of rain (890 mm). Due to the country’s very varied geography, including relief or topography, distance from the sea, etc., there is a significant variance in the amount of rainfall it receives each year. On average, India receives approximately 1,170 millimeters (46 inches) of rainfall annually. However, it is important to note that the distribution of rainfall is not uniform throughout the country. The coastal regions along the western coast, such as the Western Ghats and the northeastern states, receive higher rainfall, ranging from 2,500 to 5,000 millimeters (98 to 197 inches) annually.

In contrast, the northwest region, including Rajasthan and parts of Gujarat, experiences lower rainfall, ranging from 100 to 500 millimeters (4 to 20 inches) annually, making it more arid and prone to droughts. The central and northern parts of India receive moderate rainfall, with an average range of 500 to 1,000 millimeters (20 to 39 inches) per year.

Rainfall in India

Rainfall in India UPSC

Aspirants preparing for the UPSC Exam should pay particular attention to the Rainfall in India chapter of geography as it is extremely important. The topic forms a significant part of the physical, economic and human Geography of India.

The topic of rainfall in India is covered under the Geography subject in the UPSC syllabus. A thorough understanding of this topic is valuable for aspirants preparing for the UPSC exams to tackle questions related to India’s climate and its impact on various sectors.

Rainfall in India UPSC Questions

Rainfall in India has been a popular topic of questions in the UPSC Prelims and Mains exams. Below is an example of a sample question for reference. Candidates can also solve UPSC Previous year question paper to understand the type of question that can be asked in the examination.

Question: Mumbai receives about 190 cm of rainfall during the summer monsoon period, while Pune, barely 160 km away from Mumbai, receives only 50 cm of rainfall. What could be the probable cause for this uneven distribution of rainfall in India? (1) Pune is away from the coast, and the monsoon dries up by the time they reach this place, (2) Mumbai is at the coast, while Pune is located in the ‘rain shadow’ area of the Western Ghats

Select the correct code: (A) Only 1 is true, (B) Only 2 is true, (C) Both 1 and 2 are true, (D) Neither 1 nor 2 is true

Answer: (B) Only 2 is true

Question: Meghalaya gets the maximum rainfall in India because: (A) It is surrounded by tall mountains, (B) It is very near to the coast, (C) Its hills are funnel-shaped, which entrap the moisture-laden winds, (D) Dense forest cover attracts moisture-laden winds.

Answer: (C) Its hills are funnel-shaped, which entrap the moisture-laden winds

Question for UPSC Mains: Examine the significance of the southwest and northeast monsoons in India’s rainfall regime. Discuss their characteristics, spatial distribution, and the role they play in shaping the country’s agricultural practices, hydrology, and overall socio-economic development.

Question for UPSC Mains: Explain the factors responsible for the spatial and temporal variations in rainfall patterns in India. Analyze the role of topography, regional wind patterns, and the influence of nearby water bodies in shaping the monsoon season.

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