GeographyICSE Class 10 · Climate

Monsoon Mechanism and the Four Seasons of India (ICSE Class 10)

Updated 17 October 2026 · Draft, not yet fact-checked

The monsoon is a seasonal reversal of winds. In summer, intense heating creates low pressure over north-western India; the south-east trade winds cross the equator, are deflected to the right and blow as moist south-west winds, giving heavy rain from June to September. In winter, high pressure over the land sends dry north-east winds seaward. India has four seasons: hot weather (March-May), south-west monsoon (June-September), retreating monsoon (October-November) and cold weather (December-February).

Understand Monsoon Mechanism and the Four Seasons of India

1. Meaning and mechanism of the monsoon. The word "monsoon" comes from the Arabic *mausim*, meaning season. It is a seasonal reversal of wind direction.

Summer (south-west monsoon). The land heats faster than the sea. By May, a large low-pressure area builds over north-western India and Pakistan while the cooler Indian Ocean has higher pressure. The south-east trade winds of the southern hemisphere cross the equator, are deflected to their right by the earth's rotation, and blow as south-west winds towards the low. After crossing thousands of kilometres of warm ocean they are full of moisture and bring heavy rain. The northward shift of the inter-tropical convergence zone and of the westerly jet stream north of the Himalayas helps the monsoon to set in.
Winter (north-east monsoon). Land cools faster than the sea, so high pressure builds over north-western India and Central Asia and the seas to the south have lower pressure. Dry winds blow from land to sea from the north-east; where they cross the Bay of Bengal they pick up moisture and give winter rain on the Tamil Nadu coast.

2. Hot weather season (March to May).

Temperature: rises from south to north; north-western India reaches 45 °C or more in May, while coastal places stay milder.
Pressure and winds: low pressure over the north-west; variable winds.
Local winds and storms: *loo* (hot, dry afternoon wind of the northern plains); *dust storms* in Rajasthan and Punjab; *Kalbaisakhi* or Nor'westers (violent evening thunderstorms with rain in West Bengal and Assam, called "tea showers" in Assam); *mango showers* in Kerala and coastal Karnataka; *blossom (cherry) showers* in Karnataka that help coffee flowers.

3. South-west monsoon season (June to September).

The monsoon reaches the Kerala coast around 1 June and covers the whole country by early July (normal date about 8 July). It splits into two branches because of the shape of the peninsula.
Arabian Sea branch: strikes the Western Ghats and gives heavy orographic rain on the windward side (Mumbai, the Konkan coast). The leeward side (for example Pune) lies in the rain shadow. In Gujarat and Rajasthan the Aravallis lie parallel to the winds and do not block them, so Rajasthan gets little rain.
Bay of Bengal branch: moves towards Myanmar and north-east India; the funnel-shaped Khasi hills trap it and give some of the world's heaviest rain at Mawsynram and Cherrapunji. Blocked by the Himalayas, it turns west along the Ganga valley, and rainfall decreases westwards (Kolkata, Patna, Delhi).
Tamil Nadu coast gets little rain in this season because it lies in the rain shadow of the Western Ghats and parallel to the Bay of Bengal branch.
Breaks in the monsoon are dry spells of a few days or weeks.

4. Retreating monsoon season (October to November).

Low pressure over the north-west weakens and shifts to the Bay of Bengal, and the south-west monsoon withdraws gradually.
Clear skies, high humidity and rising temperature bring the oppressive "October heat".
Little rain on most of India, but the east coast, especially Tamil Nadu, gets heavy rain. Tropical cyclones form over the Bay of Bengal and strike the eastern coast.

5. Cold weather season (December to February).

Temperatures fall from south to north; the northern plains are cold, with frost at times, while the south stays warm. Pressure is high over the north-west and dry north-east winds blow.
Western disturbances are temperate cyclones that start over the Mediterranean Sea and are carried east by the westerly jet stream. They give light winter rain to Punjab, Haryana and western Uttar Pradesh (good for the rabi wheat crop) and snowfall in Jammu and Kashmir and Himachal Pradesh.
The north-east monsoon gives winter rain to the Tamil Nadu coast.

6. Reading climate data. Annual range of temperature = highest monthly mean - lowest monthly mean (in °C). Total rainfall = sum of monthly figures. A small range suggests a coastal station; a large range suggests an inland one. Heaviest rain in June-September points to the south-west monsoon.

Monsoon Mechanism and the Four Seasons of India: key facts

Seasons: Hot weather March to May
South-west monsoon June to September
Retreating monsoon October to November
Cold weather December to February
Pressure and winds: Summer: low pressure over the north-west, south-west winds | Winter: high pressure over the north-west, north-east winds
Local winds and showers: Loo northern plains
Kalbaisakhi West Bengal and Assam
Mango showers Kerala and Karnataka
Blossom showers Karnataka
Rainfall highlights: Mawsynram and Cherrapunji heaviest
Mumbai windward
Pune rain shadow
Tamil Nadu winter rain from the north-east monsoon
Climate data: $A nn u a l r an g e = hi g h es t m e an - l o w es t m e an (in ° C) ∣ T o t a l r ain f a l l = s u m o f m o n t h l y v a l u es (in c m) ∣ L a r g er an g e : in l an d ∣ S ma l l r an g e : co a s t a l$

Hot weather	March to May
South-west monsoon	June to September
Retreating monsoon	October to November
Cold weather	December to February

Loo	northern plains
Kalbaisakhi	West Bengal and Assam
Mango showers	Kerala and Karnataka
Blossom showers	Karnataka

Mawsynram and Cherrapunji	heaviest
Mumbai	windward
Pune	rain shadow
Tamil Nadu	winter rain from the north-east monsoon

How to answer Monsoon Mechanism and the Four Seasons of India questions

For monsoon and season questions follow a cause-effect chain.

1Name the season and its months.
2Describe pressure over the north-west (low in summer, high in winter).
3Give the wind direction, using the pressure difference as the reason.
4State where it rains and the type of rain (orographic, convectional, cyclonic).
5Add the named local wind, storm or cyclone for the season.
6For climate data, compute range and total rainfall with units, then decide coastal or inland.

Monsoon Mechanism and the Four Seasons of India in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Planning a trip around the weather

Suppose a family wants to visit Mumbai and Pune in July, and also wants to know where to expect snow in January. They check the season pattern: the Arabian Sea branch of the monsoon is active in July.

Predict the contrast between the rain at the two cities in July and name the cause of January snow in Kashmir.

Try it first, then show the solutionSolution

Mumbai lies on the windward side of the Western Ghats and gets heavy rain; Pune lies on the leeward side in the rain shadow and gets much less.
January snowfall in Kashmir is caused by western disturbances, temperate cyclones from the Mediterranean region.

Answer: Mumbai: heavy rain; Pune: rain shadow. Kashmir snow: western disturbances.

Memory hook: Windward wet, leeward dry.

Tricks to remember Monsoon Mechanism and the Four Seasons of India

Short memory aids. Say each one aloud once, then use it on a question the same day.

Heat makes low, low draws wind
Summer heating gives low pressure over land; winds flow in from the sea. Winter cooling gives high pressure; winds flow out.
Use it when: Mechanism questions.
Two branches, two destinations
Arabian Sea branch: Western Ghats. Bay of Bengal branch: Khasi hills and the Ganga valley.
Use it when: Rainfall distribution questions.
W for winter west
Western disturbances bring winter rain and snow to the north-west.
Use it when: Winter rain questions.

Monsoon Mechanism and the Four Seasons of India: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Season and months · 2 marks · Short answerBoard level

State the months of the retreating monsoon season and two features of it.

Try it first, then show the solutionSolution

It lasts from October to November.
Features: clear skies with high humidity (October heat) and cyclones along the east coast with rain on the Tamil Nadu coast.

Answer: October to November; October heat and cyclonic rain on the east coast.

Example 2: Local wind · 2 marks · Short answerBoard level

Name the local wind or storm associated with (a) the northern plains in the hot weather season, (b) West Bengal and Assam in April-May.

Try it first, then show the solutionSolution

(a) Loo: a hot, dry afternoon wind.
(b) Kalbaisakhi (Nor'westers): violent evening thunderstorms with rain.

Answer: (a) Loo (b) Kalbaisakhi.

Example 3: Winter reversal · 3 marks · Short answerHarder board level

Explain how the winter (north-east) winds arise over India and why only the Tamil Nadu coast gets rain from them.

Try it first, then show the solutionSolution

In winter the land cools faster than the sea, so high pressure builds over north-western India and Central Asia while the seas to the south have lower pressure; winds blow from land to sea from the north-east.
These winds are dry over land.
They pick up moisture crossing the Bay of Bengal and shed it as rain when they reach the Tamil Nadu (Coromandel) coast.

Answer: Land cools, high pressure forms and winds blow seaward; they pick up moisture over the Bay of Bengal and rain on the Tamil Nadu coast.

Example 4: Reading a climate table · 3 marks · Short answerHarder board level

A station records a highest monthly mean temperature of 31.6 °C in May and a lowest of 24.8 °C in January. Its heaviest monthly rainfall is in July (62 cm), and the six wettest months give a total of 241 cm. (a) Find the annual range of temperature. (b) Is the station coastal or inland? Give a reason. (c) Which winds bring its rain?

Try it first, then show the solutionSolution

(a) 31.6 - 24.8 = 6.8 °C.
(b) A small range shows a maritime (coastal) station.
(c) The south-west monsoon, as the heaviest rain is in July.

Answer: (a) 6.8 °C (b) Coastal, because the range is small (c) The south-west monsoon.

Example 5: Compare and explain · 4 marks · Long answerHOTS / competency

Account for the following: (a) Pune receives much less rain than Mumbai in the monsoon, though both lie near the Western Ghats. (b) Tamil Nadu gets most of its rain in October to December. (c) Rajasthan receives little rain from the Arabian Sea branch. (d) Cherrapunji receives very heavy rainfall.

Try it first, then show the solutionSolution

(a) Pune is on the leeward side in the rain shadow; the winds descending the Ghats are dry.
(b) The north-east winds pick up moisture over the Bay of Bengal in the retreating monsoon and shed it on the Coromandel coast.
(c) The Aravallis lie parallel to the winds and do not stop them, so they pass without rising to form rain.
(d) The funnel-shaped Khasi hills trap the moist Bay of Bengal branch.

Answer: (a) Rain shadow (b) Retreating/north-east monsoon over the Bay of Bengal (c) Aravallis parallel to the winds (d) Khasi hills funnel and trap the winds.

Where students lose marks in Monsoon Mechanism and the Four Seasons of India

The slips examiners see most often, and what to write instead.

Mistake: Missing units or arithmetic errors in climate data
The annual range is written as a number only or the subtraction is wrong.
Wrong working
Range = 23.6
Right working
Range = 38.2 - 14.6 = 23.6 °C
Do this: Show the subtraction and the unit.
Usually costs: 1 mark.
Mistake: Confusing the retreating monsoon with the north-east monsoon
The retreating monsoon is the withdrawal of the south-west monsoon; the north-east monsoon is the winter wind.
Do this: Date it: October-November retreat; December-February north-east winds.
Usually costs: 1 to 2 marks.
Mistake: Giving the wrong reason for Pune's low rain
Candidates do not mention the Western Ghats or the rain shadow.
Do this: Always name the relief barrier and windward/leeward.
Usually costs: Full mark.
Mistake: Naming tropical cyclones for Kashmir snowfall
Snow in Kashmir comes from western disturbances, not tropical cyclones.
Do this: Winter in the north-west means temperate cyclones.
Usually costs: Full mark.

Exam tips

Name the pressure belt and the wind direction in every mechanism answer.
For rainfall contrasts, name the relief (Western Ghats, Khasi hills, Aravallis).
Give months for every season as written in the syllabus.
In data questions, write each step: subtraction for range, addition for total, then the conclusion.

Practice questions on Monsoon Mechanism and the Four Seasons of India

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Western disturbances bring winter rain to:
(a) Tamil Nadu
(b) Kerala
(c) Punjab and Haryana
(d) Assam
Hint
North-west India.
Answer
(c) Punjab and Haryana.
Q2 · 1 mark · MCQBoard level
The monsoon winds in summer blow from the:
(a) north-east
(b) south-west
(c) north-west
(d) south-east
Hint
Named after their direction.
Answer
(b) south-west.
Q3 · 2 marks · Short answerBoard level
What are the "mango showers"? State where they occur and their use.
Hint
Pre-monsoon.
Answer
Pre-monsoon showers in Kerala and coastal Karnataka that help the mango crop to ripen.
Q4 · 2 marks · Short answerHarder board level
Give two differences between the south-west monsoon and the retreating monsoon.
Hint
Direction and rainfall.
Answer
South-west monsoon (June-September) blows from the sea to the land and gives rain to most of India; the retreating monsoon (October-November) is the withdrawal from land to sea and gives rain mainly to the east coast, with cyclones.
Q5 · 2 marks · Short answerHarder board level
Explain why temperate cyclones (western disturbances) are less destructive than tropical cyclones.
Hint
Strength and area.
Answer
They are weaker with lower wind speeds, give light rain over a wide area, and form over a cooler sea and travel over land rather than drawing energy from a warm sea.
Q6 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Winter rain in the north-west plains helps the rabi crops.
Reason (R): Western disturbances bring light rain in winter.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Which crop gets the rain?
Answer
(a).
Q7 · 4 marks · Long answerHarder board level
A station has these data: highest monthly temperature 38.2 °C (May), lowest 14.6 °C (January); monthly rainfall (cm): Jun 8, Jul 21, Aug 19, Sep 10, and 2 cm for the other eight months combined. (a) Find the annual range. (b) Find the total rainfall. (c) Is the station coastal or inland? (d) Name the season in which it receives most rain and the winds responsible.
Hint
Show subtraction and addition.
Answer
(a) 38.2 - 14.6 = 23.6 °C. (b) 8 + 21 + 19 + 10 + 2 = 60 cm. (c) Inland, because the range is large. (d) June to September, by the south-west monsoon.
Q8 · 4 marks · Long answerHOTS / competency
The Himalayas act as a climatic barrier for India. Case: a student claims that without the Himalayas north India would receive more rain and be warmer all year. (a) Is she right about rain? (b) Is she right about winter temperature? Give reasons using the monsoon winds and Central Asian winds.
Hint
Two roles of the mountains.
Answer
(a) No. The Himalayas stop the moist monsoon winds from escaping north and force them to shed rain over India; without them the rain would be much less. (b) No. They block the cold, dry winds from Central Asia in winter; without them the north would be colder.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Months of the south-west monsoon season?Show answer
June to September.
2.Two branches of the south-west monsoon?Show answer
Arabian Sea branch and Bay of Bengal branch.
3.Where is the highest rainfall in India during the monsoon?Show answer
Mawsynram and Cherrapunji.
4.Cause of snowfall in Kashmir in winter?Show answer
Western disturbances.
5.Meaning of "monsoon"?Show answer
Season (from the Arabic mausim).

Monsoon Mechanism and the Four Seasons of India: frequently asked questions

What causes the monsoon?

Seasonal differences in heating of land and sea create a pressure contrast that reverses the winds.

Why does the Tamil Nadu coast get rain in winter?

The north-east winds pick up moisture over the Bay of Bengal and shed it on the Coromandel coast.

What is the loo?

A hot, dry wind blowing in the afternoons over the northern plains in summer.

What is "October heat"?

The hot, humid, oppressive weather of the retreating monsoon season.