Last reviewed 30 Sept 2026 · 10 min read
Climate of India
India has a tropical monsoon climate. The Tropic of Cancer (23½° N) passes through the middle of the country, dividing it almost into two halves — a tropical south and a sub-tropical north. Even so, the whole country shows a monsoon rhythm: the rainy season and the dry season, with a reversal of wind direction between them.
Factors that shape the climate
| Factor | Effect |
|---|---|
| Latitude | the Tropic of Cancer divides the country; the south is hot all year, the north has seasonal extremes |
| Himalayas | act as a climatic barrier — they keep the cold Central Asian winds out and force the monsoon winds to rain on the Indian side |
| Distance from the sea (continentality) | coastal areas (Mumbai, Chennai) have a moderate (equable) climate; interior places (Delhi, Nagpur) show extremes |
| Altitude | temperature falls about 6.5 °C for every 1000 m of height (the normal lapse rate) — hill stations are cool |
| Relief | the Western Ghats get heavy rain on the windward side; the rain-shadow area (the Deccan interior) is dry; the Thar Desert is dry because the Aravallis lie parallel to the monsoon branch |
| Monsoon winds | the most important factor |
| Jet streams | westerly jet streams over north India in winter bring western disturbances; the tropical easterly jet helps the onset of the monsoon |
| Ocean currents, El Niño and La Niña | affect the monsoon's strength |
The monsoon
The word monsoon comes from the Arabic mausim (season). The monsoon is a seasonal reversal of winds. In summer, the land heats up faster than the sea, creating a low pressure over north-west India, so moist winds blow from the sea to the land (south-west monsoon). In winter, the land cools faster; high pressure over the land causes dry winds from the land to the sea (north-east monsoon).
Mechanism (modern view)
- The shift of the Inter-Tropical Convergence Zone (ITCZ) northward over the Ganga plain in summer; the south-east trade winds of the southern hemisphere cross the equator and turn right (Coriolis force) into the south-west monsoon.
- The Tibetan plateau heats up strongly, drawing in the monsoon; the Tropical Easterly Jet stream over the peninsula assists the "burst" of the monsoon.
- Normal date of onset over the Kerala coast: about 1 June; it covers the whole country by about 8 July (a recent shift to 8 July from 15 July was made in the IMD's normals); the withdrawal begins in north-west India in September.
- The monsoon has two branches: the Arabian Sea branch (rains on the Western Ghats first; Mumbai; passes to Gujarat and Rajasthan with little rain) and the Bay of Bengal branch (enters via the north-east and turns west along the Himalayan foothills, giving heavy rains to the Ganga plain).
- Breaks in the monsoon: dry spells within the rainy season.
- Mango showers (pre-monsoon showers in Kerala and Karnataka, help mangoes ripen), Kalbaisakhi (Norwesters, thunderstorms in Bengal and Assam in April–May), Loo (hot, dry wind in the north-west plains in summer), Blossom showers (coffee flowers in Karnataka).
- El Niño (warming of the Pacific off Peru) usually weakens the Indian monsoon and causes drought; La Niña usually strengthens it. The Indian Ocean Dipole (IOD) — a positive phase helps the monsoon.
The four seasons
| Season | Months | Features |
|---|---|---|
| Cold weather (winter) | December–February | clear skies, low humidity, cool north (Jan is the coldest month), western disturbances bring winter rain to north-west India (useful for the rabi crop, especially wheat); the north-east monsoon rains Tamil Nadu in October–December |
| Hot weather (summer) | March–May | temperatures rise, loo in the north; the highest temperatures are recorded in Rajasthan and the plains; pre-monsoon showers |
| South-west monsoon (rainy) | June–September | about 75 % of the annual rainfall; Mawsynram and Cherrapunji (Meghalaya) get the highest rainfall in the world (Mawsynram is the wettest); the Thar gets very little |
| Retreating (post-)monsoon | October–November | withdrawal of the monsoon; clear skies; "October heat"; cyclones in the Bay of Bengal hit the east coast (Odisha, Andhra Pradesh, Tamil Nadu) |
Rainfall distribution
- Very heavy (over 250 cm): the Western Ghats windward slopes, the north-eastern states (Meghalaya, Assam hills), the sub-Himalayan West Bengal and the Andaman & Nicobar Islands.
- Heavy (200–250 cm), moderate (100–200 cm): parts of the Ganga plain, the east coast, Odisha and Chhattisgarh.
- Low (50–100 cm): the Deccan interior, eastern Rajasthan, Punjab, Haryana, western UP.
- Very low (< 50 cm): west Rajasthan (Thar), Ladakh, parts of Gujarat, and Karnataka's rain-shadow area; Jaisalmer is among the driest places.
- Average annual rainfall of India: about 117 cm. Rainfall is highly variable and depends on the monsoon.
- The Andaman & Nicobar Islands get the earliest monsoon rains (about mid-May). The coldest inhabited place in India is Dras (Ladakh); Leh is a cold desert. The hottest places are in the Thar and the plains (Sri Ganganagar, Banda and others).
- Climate classification: Köppen — India has climate types such as Am (tropical monsoon), Aw (tropical savanna), BSh (semi-arid), BWh (arid), Cwg (humid sub-tropical) and E (polar/mountain). Koeppen's system is the one used in exams.