Climate & Weather

About 7 min · Geography · English

Time worked out from the lesson's 458 words at 150 words a minute, plus a minute for each question.

Understanding the Indian monsoon system is particularly important since Uttar Pradesh's agriculture, water resources, and economy are directly tied to monsoon patterns. Beyond India, you must know the basic classification of world climate types and atmospheric phenomena like El Niño and La Niña that affect global weather patterns.

Key ideas

Monsoon derives from Arabic "mausim" (season); refers to seasonal reversal of wind direction. India receives 75–90% of annual rainfall during the southwest monsoon (June–September).
Indian climate is tropical monsoon type, characterised by hot summers, moderate winters, and concentrated rainfall in 3–4 months. The Himalayas block cold Central Asian winds, while the Thar Desert creates low pressure attracting monsoon winds.
Four major seasons in India: Winter (Jan–Feb), Pre-monsoon/Summer (Mar–May), Southwest Monsoon (Jun–Sep), Post-monsoon/Northeast Monsoon (Oct–Dec). Tamil Nadu receives most rain in the post-monsoon season.
Jet streams are high-altitude westerly winds that influence monsoon onset and withdrawal. The subtropical westerly jet stream's northward shift in summer allows monsoon winds to enter India.
El Niño is the warming of Pacific Ocean surface waters off South America, occurring every 2–7 years. It weakens the Indian monsoon, causing droughts. La Niña is the cooling phase, often bringing excess rainfall and floods to India.

Watch out for

Confusing weather and climate → Weather is short-term (today's rain); climate is long-term average (monsoon pattern over decades). Exam questions use these terms precisely.
Thinking all of India gets monsoon rain simultaneously → The monsoon progresses gradually. Kerala receives it first (June 1), North India by mid-June, and western Rajasthan last (around 8 July). Know the progression pattern.
Mixing up El Niño and La Niña effects → El Niño = warm Pacific waters = weak Indian monsoon = drought. La Niña = cool Pacific waters = strong monsoon = floods. They are opposite phenomena.

Quick reference

Indian monsoon = southwest (Jun–Sep) + northeast (Oct–Dec); 75% rainfall in SW monsoon.
Mawsynram (Meghalaya) = wettest place in India; Jaisalmer (Rajasthan) = driest.
El Niño = Pacific warming = Indian drought; La Niña = Pacific cooling = excess rain.
Western Disturbances = winter extratropical storms = North India winter rain.
ITCZ northward shift in summer = pulls monsoon winds into India.

Check yourself: 3 questions

1. The Indian monsoon is primarily caused by which of the following factors?
2. El Niño events in the Pacific Ocean typically result in which of the following effects on the Indian monsoon?
3. Which one of the following Indian cities experiences an equable climate throughout the year due to its proximity to the sea?

This lesson is cut from the topic's note, not rewritten. Fact-checked on 17 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.

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