Why this matters now
The monsoon is examined every year — its mechanism, the factors controlling India’s climate, the four seasons, and the role of El Niño / La Niña and the Indian Ocean Dipole in monsoon variability (a recurring current-affairs link to food prices and the economy).
Factors that control India’s climate
- Latitude — the Tropic of Cancer passes through the middle, so the south is tropical and the north sub-tropical;
- Altitude & the Himalayas — block cold Central Asian winds and the retreating monsoon, giving India warmer winters and concentrated rainfall;
- Pressure & winds — the seasonal shift of pressure belts and the monsoon winds;
- Distance from the sea — coastal areas have an equable climate; the interior is continental (extreme);
- Relief — windward slopes (Western Ghats, Meghalaya) get heavy rain; leeward/rain-shadow areas stay dry.
The four seasons
| Season | Months |
|---|---|
| Cold weather (winter) | December-February |
| Hot weather (summer) | March-May (loo, pre-monsoon showers) |
| Advancing (south-west) monsoon | June-September — the main rainy season |
| Retreating monsoon (post-monsoon) | October-November (cyclones on the east coast) |
The monsoon mechanism
The southwest monsoon is driven by the differential heating of land and sea and the northward shift of the Inter-Tropical Convergence Zone (ITCZ) in summer, which draws moisture-laden winds from the Indian Ocean over the subcontinent. Other influences: the subtropical jet stream and tropical easterly jet, the Tibetan Plateau heating, and the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), which modulate how strong the monsoon is in a given year.
UPSC angle
Know the controlling factors, the four seasons, and the monsoon mechanism (ITCZ, differential heating, jets). Link El Niño/La Niña and the IOD to monsoon performance and food inflation.
Frequently asked questions
Why is India’s climate called the monsoon type?
Because it is dominated by the seasonal reversal of winds — the southwest monsoon (June-September) and the retreating monsoon — that governs India’s rainfall and agriculture.
What factors control the climate of India?
Latitude (Tropic of Cancer), altitude and the Himalayas, pressure and winds, distance from the sea, and relief (windward vs rain-shadow).
What are the four seasons of India?
Cold weather (Dec-Feb), hot weather (Mar-May), the advancing southwest monsoon (Jun-Sep), and the retreating monsoon (Oct-Nov).
How do El Niño and the IOD affect the monsoon?
El Niño tends to weaken the monsoon (and La Niña to strengthen it), while a positive Indian Ocean Dipole generally aids monsoon rainfall — so they are key to year-to-year variability.