Climate of India for UPSC Prelims
1. Introduction to India’s Climate
India’s climate is characterized by significant regional variations, primarily influenced by the monsoon system, topography, and geographical location. Ranging from tropical to temperate zones, India experiences diverse climatic conditions, from arid deserts to humid coastal regions. The climate plays a critical role in shaping agriculture, water resources, and livelihoods, making it a key topic for UPSC Prelims in Indian geography. Understanding the factors driving these variations is essential for grasping India’s environmental and socioeconomic dynamics.
Key Facts
- Climate Type: Tropical monsoon with regional variations
- Major Influence: Southwest monsoon, 70–90% of annual rainfall
- Climatic Zones: Tropical, arid, temperate, alpine
- Significance: Impacts agriculture, economy, and disaster management
Important Facts for UPSC
- India’s climate is classified as ‘Am’ (tropical monsoon) under Köppen’s system.
- The monsoon provides ~880 mm of average annual rainfall in India.
- Climatic diversity supports six major agro-ecological zones in India.
2. Characteristics of India’s Climate
Overview
India’s climate is predominantly tropical monsoon, marked by distinct wet and dry seasons, high temperatures, and significant rainfall variations.
Key Features
- Monsoon Dominance: Southwest monsoon (June–September) brings most rainfall.
- Temperature Variations: Coastal areas have moderate temperatures; interiors face extremes (e.g., Rajasthan).
- Rainfall Patterns: Varies from 100 mm (Thar Desert) to 11,000 mm (Cherrapunji).
- Seasonality: Four seasons—summer, monsoon, post-monsoon, winter.
Important Facts for UPSC
- Cherrapunji, Meghalaya, holds the record for the highest annual rainfall globally.
- Rajasthan’s Thar Desert is India’s driest region, with <250 mm rainfall.
- Coastal areas like Mumbai have high humidity, moderating temperatures.
3. Factors Influencing India’s Climate
Overview
India’s climate is shaped by multiple geographical and atmospheric factors, creating diverse climatic conditions.
Major Factors
| Factor |
Description |
Impact |
| Latitude |
India lies between 8°N and 37°N |
Tropical climate in south, temperate in north |
| Altitude |
Himalayas and plateaus affect temperature |
Cooler climates in hilly areas (e.g., Shimla) |
| Monsoon Winds |
Seasonal wind reversal |
Heavy rainfall in summer, dry winters |
| Topography |
Himalayas, Ghats influence rainfall |
Rain shadow in Deccan, heavy rain in Ghats |
| Ocean Proximity |
Arabian Sea, Bay of Bengal |
Moderate coastal climates, cyclones |
| Jet Streams |
Upper atmospheric winds |
Guides monsoon and western disturbances |
Important Facts for UPSC
- The Himalayas block cold winds, keeping India warmer in winter.
- The Western Ghats cause orographic rainfall, up to 2,500 mm annually.
- The Somali Jet strengthens the southwest monsoon over India.
4. The Indian Monsoon System
Overview
The monsoon is the backbone of India’s climate, driven by differential heating of land and sea, delivering 70–90% of annual rainfall.
Mechanism
- Southwest Monsoon: June–September, low pressure over Northwest India attracts moist winds from the Arabian Sea and Bay of Bengal.
- Northeast Monsoon: October–December, brings rain to Tamil Nadu and Andhra Pradesh.
- ITCZ Shift: Northward movement in summer triggers monsoon onset.
Branches
- Arabian Sea Branch: Heavy rain along Western Ghats and West India.
- Bay of Bengal Branch: Rainfall in Northeast and Gangetic Plains.
Important Facts for UPSC
- Monsoon onset begins in Kerala around June 1, covering India by mid-July.
- The northeast monsoon contributes 30–50% of Tamil Nadu’s rainfall.
- Monsoon breaks (dry spells) occur due to ITCZ fluctuations.
5. Climatic Regions of India
Overview
India is divided into distinct climatic regions based on temperature, rainfall, and vegetation.
Major Regions
| Region |
Location |
Climate Type |
Characteristics |
| Tropical Wet |
Western Ghats, Northeast |
Monsoon |
High rainfall (>2,000 mm), evergreen forests |
| Tropical Dry |
Deccan, Central India |
Savanna |
Moderate rainfall (700–1,000 mm), deciduous forests |
| Arid |
Rajasthan, Gujarat |
Desert |
Low rainfall (<250 mm), sparse vegetation |
| Semi-Arid |
Punjab, Haryana |
Steppe |
250–500 mm rainfall, grasslands |
| Temperate |
Himalayas |
Alpine |
Cold winters, moderate summers, coniferous forests |
Important Facts for UPSC
- The tropical wet region includes India’s wettest areas (e.g., Mawsynram).
- The arid region covers ~12% of India’s land area, mainly Thar Desert.
- The temperate Himalayan region supports apple orchards in Himachal.
6. Seasonal Variations in India
Overview
India experiences four distinct seasons, each with unique climatic characteristics.
Seasons
- Summer (March–May): High temperatures (40–50°C in Rajasthan), pre-monsoon showers (Nor’westers in Bengal).
- Monsoon (June–September): Heavy rainfall, flooding in lowlands, vital for agriculture.
- Post-Monsoon (October–November): Transition period, northeast monsoon in South India, cyclones in eastern coast.
- Winter (December–February): Cool temperatures (5–15°C in North), western disturbances bring rain to Punjab.
Important Facts for UPSC
- Nor’westers (Kalbaisakhi) bring pre-monsoon storms to Northeast India.
- Winter rainfall in Northwest India is due to western disturbances.
- Cyclones peak in October–November, affecting Odisha and Andhra Pradesh.
7. Climate Phenomena (El Niño, La Niña, IOD)
Overview
Global climatic phenomena significantly influence India’s monsoon and weather patterns.
Key Phenomena
- El Niño: Warmer Pacific waters weaken monsoon, causing droughts (e.g., 2009).
- La Niña: Cooler Pacific waters strengthen monsoon, leading to floods (e.g., 2010).
- Indian Ocean Dipole (IOD): Positive IOD (warmer western Indian Ocean) boosts monsoon; negative IOD weakens it.
Important Facts for UPSC
- 60% of El Niño years lead to below-normal monsoon rainfall in India.
- Positive IOD in 2019 enhanced monsoon despite a weak El Niño.
- India Meteorological Department (IMD) monitors ENSO and IOD for forecasts.
8. Impact of Climate Change on India
Overview
Climate change is altering India’s weather patterns, increasing the frequency and intensity of extreme events.
Key Impacts
- Monsoon Variability: Erratic rainfall, delayed onset, and intense bursts.
- Temperature Rise: India warmed by ~0.7°C since 1901, heatwaves more frequent.
- Sea Level Rise: Threatens coastal cities like Mumbai, Chennai.
- Glacial Retreat: Himalayan glaciers (e.g., Gangotri) shrinking, affecting river flows.
Mitigation Efforts
- National Action Plan on Climate Change (NAPCC), launched 2008.
- India’s Paris Agreement target: 40% non-fossil energy by 2030.
- International Solar Alliance, co-founded by India in 2015.
Important Facts for UPSC
- India ranks 7th on the Global Climate Risk Index (2021).
- Glacial retreat threatens 30% of Himalayan river flows by 2050.
- India aims for net-zero carbon emissions by 2070.
9. Socioeconomic and Environmental Impact
Socioeconomic Role
- Agriculture: Monsoon-dependent farming supports 50% of India’s workforce.
- Water Resources: Rainfall recharges rivers, lakes, and groundwater.
- Economy: Climate impacts GDP, especially agriculture (~15% of GDP).
Environmental Challenges
- Floods and Droughts: Affect 40 million hectares annually.
- Cyclones: Eastern coast faces 80% of India’s cyclones.
- Biodiversity Loss: Climate shifts threaten species in Western Ghats.
Important Facts for UPSC
- Monsoon failure in 2015 caused a 10% drop in kharif crop output.
- Cyclone Amphan (2020) caused ₹1.5 lakh crore in damages.
- Western Ghats host 30% of India’s endemic species, at risk from warming.
10. Significance for Geography
Geographical Significance
India’s climate shapes its topography, vegetation, and drainage systems, creating diverse geographical regions.
Environmental Significance
Climatic variations support rich ecosystems but face threats from climate change and human activity.
Socioeconomic Significance
The climate drives agriculture, water management, and disaster preparedness, requiring adaptive strategies.
UPSC Relevance
Climate of India is a core topic in Indian geography, tested for its factors, variations, and impacts in Prelims.
Important Facts for UPSC
- India’s climate supports six major soil types, linked to rainfall patterns.
- Monsoon forecasting by IMD aids agricultural planning.
- National Disaster Management Authority (NDMA) addresses climate-related hazards.
UPSC Preparation Tips
- Memorize climatic regions, monsoon branches, and seasonal characteristics.
- Understand factors influencing climate (latitude, topography, jet streams).
- Focus on monsoon mechanism and its socioeconomic importance.
- Link climate phenomena (El Niño, IOD) to monsoon variability.
- Practice map-based questions on climatic zones and rainfall distribution.
- Revise key terms (orographic rain, ITCZ, western disturbances) and climate change initiatives.