CLIMATE OF INDIA

Tropical monsoon climate • 4 seasons • 6 major climate zones • Two monsoons • From -45°C in Ladakh to 51°C in Rajasthan

1. Major Climate Zones of India

🏔️ Alpine / Himalayan

Region: J&K, Ladakh, Himachal, Uttarakhand, Sikkim, Arunachal >3500m

Temp: -30°C to 15°C • Rain: 100-600mm, mostly snow

TundraET / Dfc

Siachen -45°C recorded. Short summer, long freezing winter.

🌲 Humid Subtropical - Northeast

Region: Assam, Meghalaya, Arunachal foothills

Temp: 7°C - 32°C • Rain: 2000-11000mm

Wettest on EarthCwa

Mawsynram ∼11,871mm/yr, Cherrapunji. Evergreen forests.

🌾 Humid Subtropical - Gangetic Plain

Region: Punjab to West Bengal, UP, Bihar

Temp: 5°C - 45°C • Rain: 1000-2000mm

Extreme rangeCwa

Hot summer loo winds, cold winter fog, 80% rain in monsoon.

🏜️ Arid Desert - Thar

Region: Western Rajasthan, Kutch Gujarat

Temp: 0°C - 51°C • Rain: <250mm

BWhPhalodi 51°C

Huge diurnal range. Dust storms in summer.

🌵 Semi-Arid - Deccan

Region: Maharashtra, Karnataka, AP, Telangana, TN interior

Temp: 15°C - 42°C • Rain: 400-750mm

BShRain-shadow

Leeward of Western Ghats. Drought-prone, millet farming.

🌴 Tropical Wet - West Coast

Region: Kerala, Coastal Karnataka, Goa, Mumbai coast

Temp: 22°C - 32°C • Rain: 2500-5000mm

AmNo winter

First monsoon hit June 1. Coconut, spices, evergreen.

2. Köppen Classification in India

CodeTypeWhereExample
AmTropical MonsoonWest coast, NE islandsKochi, Port Blair
AwTropical SavannaPeninsular, Central IndiaChennai, Nagpur
BWhHot DesertTharJaisalmer
BShSemi-Arid SteppeDeccan, E. RajasthanHyderabad, Jaipur
CwaHumid SubtropicalGangetic plain, NEDelhi, Lucknow, Guwahati
CfbOceanic HighlandNilgiris, ShillongOoty
DfcSubarcticHigh HimalayaLeh (borderline)
ETTundra>4500m HimalayaSiachen

India is mainly tropical: Tropic of Cancer (23.5°N) divides it. South = tropical, North = subtropical.

3. Four Seasons (IMD)

❄️ Winter: Dec - Feb

Avg Temp10-25°C (North 5°C)FeatureWestern Disturbances → snow/rain in NW. Cold wave, fog in plains.

☀️ Summer: Mar - May

Avg Temp32-45°CFeatureLoo hot winds. Pre-monsoon thunderstorms: Kalbaisakhi (Bengal), Mango showers (Kerala).

🌧️ SW Monsoon: Jun - Sep

Rainfall75-80% of annual rainFeatureArabian Sea + Bay of Bengal branches. Mawsynram peak.

🍂 NE Monsoon: Oct - Nov

RainfallTN coast 50% of its rainFeatureRetreating monsoon. Cyclones in Bay of Bengal. Chennai floods.

4. Monsoon Mechanism

Why monsoon happens

Summer: Tibetan plateau heats → low pressure → moist SE trade winds from Indian Ocean deflect → SW monsoon. Winter reverses → NE dry winds.

June 1
Hits Kerala
🌊 Arabian Sea branch
→
June 7-10
Mumbai, NE
⛰️ Western Ghats orographic rain
→
July 1-15
Delhi, UP, Punjab
🌾 Full coverage
→
Oct
Retreats
🍂 From NW

Two branches

Arabian Sea BranchStronger, hits Western Ghats → 3000mm+ in 2 months. Gives Mumbai, Kerala rain.Bay of Bengal BranchHits NE → funnels up Gangetic plain. Causes floods in Assam, Bihar.

Breaks & Variability

El Niño → weak monsoon / drought. La Niña → strong monsoon / floods. Himalayas block cold Central Asian winds, keeping India warmer.

5. Factors, Temperature & Rainfall Data

Controlling factors

1. Latitude: Tropic of Cancer. 2. Himalayas: block cold winds, force monsoon lift. 3. Ocean: Indian Ocean moisture. 4. Western Disturbances: Mediterranean origin winter rain. 5. Altitude, distance from sea, jet streams.

Extreme records

RecordPlaceValue
HottestPhalodi, Rajasthan (2016)51°C
ColdestDras, Ladakh-45°C
WettestMawsynram, Meghalaya11,871 mm/yr
DriestJaisalmer, Rajasthan∼100 mm/yr

Climate change note

IMD: India warmed ∼0.7°C since 1901. More intense heavy rain events, fewer rainy days, rising sea level threatening Sundarbans & Kochi, Himalayan glaciers retreating.