Rainfall Distribution in India| Class 11 Geography Notes

Rainfall Distribution in India: India, a vast country geographically, exhibits diverse climatic conditions across its regions, leading to variations in rainfall distribution. Certain areas receive abundant rainfall, while others face scarcity. The recorded disparity between the highest and lowest rainfall in India is around 1178 cm. In this article, we will explore different zones of the country based on average annual rainfall, an important topic in the Geography Syllabus of UPSC for Prelims and Mains.

Rainfall Distribution In India: Overview

In India, rainfall varies a lot. It falls in different amounts across the country. Some places get more rain than others. On average, India gets about 115 inches (2900 mm) of rain every year. But in the western Himalayan region, it’s lower, around 50 inches (1270 mm), while in the northeast, it’s higher, about 160 inches (4000 mm).

Rainfall Distribution In India

Here’s a summary of regions categorized by their precipitation levels:

Precipitation Category	Regions Included
Heavy Precipitation (>200 cm)	Andaman and Nicobar Islands, Meghalaya, Arunachal Pradesh, Mizoram, Nagaland, Manipur, Tripura, Sikkim, Assam
Very Heavy Precipitation (>250 cm)	Coastal Karnataka, Kerala, Tamil Nadu, Lakshadweep
Extremely Heavy Precipitation (>400 cm)	West Bengal, Odisha, Assam, Meghalaya, Arunachal Pradesh
Desert and Semi-desert regions (<50 cm)	Rajasthan, Gujarat, parts of Haryana, Punjab, Jammu & Kashmir
Coastal regions (>100 cm)	Andhra Pradesh, Karnataka, Kerala, Tamil Nadu
Inland regions (>150 cm)	Maharashtra, Madhya Pradesh, Chhattisgarh, Jharkhand
Himalayan region (>200 cm)	Parts of Himachal Pradesh, Uttarakhand, Sikkim, Arunachal Pradesh

Rainfall in India varies throughout the year, with a distinct rainy season from about June to September. According to the Koppen climate classification, India can be divided into seven different climate regions:

1. Tropical semi-arid
2. Sub-tropical arid desert
3. Sub-tropical semi-arid
4. Tropical rainforest
5. Tropical Savannah
6. Sub-tropical humid
7. Alpine

The average annual rainfall in India is 118 cm, as per data from the Meteorological Department. Here’s how rainfall is distributed across different regions:

1. Extreme Precipitation regions: The northeastern regions and the windward side of the Western Ghats receive an average of 400 cm of annual rainfall. Areas like Assam, Meghalaya, Arunachal Pradesh, and hilly parts of the Western Ghats have tropical rainforests. The village of Mawsynram in Meghalaya holds the record for the highest rainfall in India and the world.
2. Heavy Precipitation regions: Regions experiencing 200-300 cm rainfall fall into this category. Most of Eastern India, including states like West Bengal, Tripura, Nagaland, Manipur, Odisha, and Bihar, are included here. This zone also covers most areas in the sub-Himalayan belt.
3. Moderate Precipitation regions: Areas with 100 to 200 cm of rainfall include parts of West Bengal, Bihar, Odisha, Madhya Pradesh, Andhra Pradesh, and the leeward side of the Western Ghats. These regions typically feature Wet Deciduous forests as their predominant natural vegetation.
4. Scanty Precipitation regions: Areas receiving 50 to 100 cm of rainfall include parts of Maharashtra, Gujarat, Karnataka, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, Punjab, Haryana, and Western Uttar Pradesh. Tropical Grasslands, Savannah, and Dry Deciduous forests are commonly found here.
5. Desert and Semi-desert Regions: These areas receive below 50 cm of rainfall. States like Rajasthan, Gujarat, and adjacent areas are classified as desert or semi-desert. Some parts of Jammu & Kashmir, like the Ladakh plateau, are considered cold deserts. Vegetation in these regions consists of hardy species adapted to extended droughts. Some areas, like parts of Gujarat, have Savannah vegetation in the wetter regions. The village of Ruyli in Rajasthan holds the record for the lowest rainfall in India.

Water Cycle

When the sun’s heat warms up lakes, seas, rivers, and plants, water turns into vapor and rises into the air. This process is called evaporation. Water also evaporates from plant leaves, which is called transpiration. As this water vapor goes up, it cools and turns back into tiny water droplets, forming clouds. This cycle of evaporation and condensation keeps going, making clouds heavier until they release rain. The rainwater then gets stored in different places like oceans, soil, glaciers, underground as groundwater, lakes, and snowfields.

Conclusion – Rainfall Distribution in India

Rainfall patterns in India are influenced by geographical features like the Thar Desert and the Himalayas. Additionally, temperature and pressure changes over the Indian Ocean, Arabian Sea, Bay of Bengal, and the southern part of the Pacific Ocean also affect the monsoon rains across the country. For UPSC aspirants, understanding monsoon rains in India is crucial for the IAS Geography syllabus. It’s a significant aspect of the physical, economic, and human Geography of the country. Therefore, questions related to rainfall are often included in UPSC question papers. It’s important for aspirants to delve deeper into this topic for comprehensive preparation.

FAQs on Rainfall Distribution in India

Which winds bring rainfall in India?

In India, the Southwest Monsoon brings most of the rain. It happens from June to September. This rain is super important for crops because they need it to grow. The Southwest Monsoon starts because of a low-pressure area over the Bay of Bengal.

What is the classification of rainfall in India?

The rainfall is classified as excess, normal deficient or scanty as per the following criteria. Excess : +20% of normal or more, ‘Normal: + 19% to -19% of normal, Deficient -20% to -59% of normal, Scanty: -60 % of normal or less. 34.5 In India, two time series data on rainfall are available and popularly used .

Where does most rainfall occur in India?

Mawsynram receives the highest rainfall in India. It is reportedly the wettest place on Earth, with an average annual rainfall of 11,872 millimetres (467.4 in). According to the Guinness Book of World Records, Mawsynram received 26,000 millimetres (1,000 in) of rainfall in 1985.

What is the distribution of rainfall in UP?

The rain in U.P. can vary from an annual average of 170 cm in hilly areas to 84 cm in Western U.P. Given the concentration of most of this rainfall in the 4 months of Monsoon period, excess rain can lead to floods and shortage to droughts.

What are the 3 main types of rainfall?

The three types of rainfall are:

• Convectional rainfall
• Orographic rainfall (also known as relief rainfall)
• Cyclonic rainfall (also known as frontal rainfall)