Rainfall Distribution
India receives an average of about 1,160 mm of annual rain, but with extremes of more than 11,000 mm in Meghalaya to less than 100 mm in western Rajasthan and Ladakh. About 75 percent falls in the south-west monsoon season.
Characteristics of Indian rainfall
- Seasonal: concentrated in June-September.
- Orographic: depends on mountain barriers.
- Erratic and variable; variability is highest in low-rainfall areas such as Rajasthan and Gujarat.
- Spatial: a gradient from the east to west in the Gangetic plain.
Rainfall regions
| Region | Annual rainfall | Areas |
|---|---|---|
| Very heavy | Above 200 cm | Western coast, Western Ghats windward side, Assam, Meghalaya, Arunachal, Tripura, Sub-Himalayan West Bengal |
| Heavy | 100-200 cm | Southern Maharashtra, Karnataka and Kerala interior, east Madhya Pradesh, Odisha, Chhattisgarh, parts of the Ganga plain |
| Moderate | 50-100 cm | Parts of Uttar Pradesh, Bihar, Gujarat, Andhra, Tamil Nadu interior, Punjab |
| Low / scanty | Below 50 cm | Western Rajasthan, Kutch, Ladakh, parts of Gujarat, Punjab, Haryana and the Deccan rain shadow |
Records to remember
| Fact | Place |
|---|---|
| Highest annual rainfall (recent decades) | Mawsynram (Meghalaya), often given as the wettest place; Cherrapunji (Sohra) is the nearby former record holder |
| Driest place by rainfall | Jaisalmer / Jaisalmer area and parts of the Thar; Leh is cold desert with very low rain |
| Rainiest Western Ghats station | Agumbe in Karnataka (called the "Cherrapunji of the south") |
| Rain-shadow cold desert | Ladakh |
Variability and drought
- Coefficient of variation of rainfall is above 50 percent in Rajasthan and Gujarat.
- Drought: meteorological drought when rainfall is below 75 percent of the normal over an area.
- Drought-prone areas: Rajasthan, Gujarat, Maharashtra (Marathwada, Vidarbha), Karnataka interior, Rayalaseema, Telangana, Bundelkhand.
- Flood-prone: Brahmaputra valley, Bihar (Kosi), eastern UP, the lower Ganga plain, coastal Odisha.
- Cloudbursts: sudden rain over 10 cm in an hour over a small area; common in the Himalayas (Uttarakhand 2013, Leh 2010, Amarnath 2022).
Keep practising
Notes are only half the work. Test yourself with questions and discuss doubts with other aspirants.
Prepared for exam revision from NCERT, standard geography textbooks, the Census of India 2011, the India State of Forest Report, IMD, Ministry of Agriculture and other official sources. Maps are schematic teaching maps, not Survey of India maps, and zone boundaries are approximate. Figures such as production, capacity, counts of parks and ports, and census status change, so check the latest official source before relying on them. Found a mistake? Tell us.