Climate of India — Part 1: Controls of climate and the monsoon: visual lesson, ICSE Class 10 Geography (H.C.G. Paper 2)

Lesson

One country, many climates

Part 1 — India has a tropical monsoon climate, yet Leh freezes while Chennai sweats, and Mawsynram floods while western Rajasthan stays dry. Several controls explain the differences.

In this lesson you will

Explain how latitude, altitude, distance from the sea, winds, the Himalayas, jet streams and El Niño affect India’s climate
Describe the pattern of temperature, rainfall and winds in summer and in winter
Explain the mechanism of the south-west monsoon

Table of four types of place in India and a typical feature of the climate of each
Place type	Typical climate feature
Himalayan town	Cold winters, snowfall
Thar desert	Very hot days, scanty rain
Konkan coast	Mild temperatures, very heavy summer rain
Tamil Nadu coast	Rain mainly in October–December

Concept

Factors affecting India’s climate (1)

Latitude: the Tropic of Cancer runs through the middle of India; the south lies in the tropical zone (hot all year), the north in the sub-tropical zone (greater seasonal contrast). Altitude: temperature falls with height (about 6.5 °C per km), so hill stations such as Shimla and Ooty are cool. Distance from the sea (continentality): the sea warms and cools slowly, so coastal places have a small annual range (equable climate) while interior places have a large range (extreme climate) — Mumbai’s range is small, Delhi’s large.

Table of three climatic factors and examples of their effects
Factor	Example of its effect
Latitude	South warmer in winter than the north
Altitude	Shimla cooler than Chandigarh in summer
Distance from sea	Mumbai equable, Delhi extreme

Concept

Factors affecting India’s climate (2)

Winds: the seasonal reversal of winds (monsoon) brings rain in summer and dry weather in winter. The Himalayas: they block the cold Central Asian winds in winter, keeping north India warmer, and force the monsoon winds to rise and shed rain over the plains. Jet streams: fast upper-air westerly winds south of the Himalayas in winter bring western disturbances; their shift north in summer, and an easterly jet over the peninsula, help the monsoon set in. El Niño: warming of the eastern Pacific Ocean every few years tends to weaken the Indian monsoon, causing droughts.

Table of four more climatic factors and their effects on India
Factor	Effect on India
Monsoon winds	Wet summers, dry winters
Himalayas	Block cold winds; cause relief rain
Jet streams	Western disturbances; monsoon onset
El Niño	Often a weak monsoon

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