Skip to content
GK24
GK NotesGeographyClimate and Rainfall of India

Climate and Rainfall of India: Monsoon, Seasons and PYQs

Climate of India notes for exams: the monsoon mechanism, four seasons, onset and retreat, rainfall distribution, local storms and El Nino effects.

By · Published · 4 min read

Climate and Rainfall of India: Monsoon, Seasons and PYQs — GK24 title card
Climate and Rainfall of India: Monsoon, Seasons and PYQs — GK24 title card

India has a tropical monsoon climate, named from the Arabic word mausim, meaning season, because its winds reverse direction between summer and winter. The whole agricultural year, the filling of reservoirs and a large part of the economy turn on a rainy season of about four months. Because the country stretches from the Himalaya to the sea and from the desert to the rainforest, almost every climatic type is found within it, and examiners test both the mechanism of the monsoon and the names of its local winds.

Why India has a monsoon climate

The Tropic of Cancer passes through the middle of the country, so the south is tropical and the north lies in the sub-tropical belt. The Himalaya blocks the cold winds of Central Asia and holds the monsoon winds over the plains, which is why north India is warmer in winter than places at the same latitude in western Asia. In summer the intense heating of the Thar desert and the northern plains creates a low pressure trough, while high pressure sits over the southern Indian Ocean. Air moves from the high to the low, and the south-east trade winds of the southern hemisphere cross the equator, turn right under the Coriolis force and arrive as the south-west monsoon. The shifting of the Inter Tropical Convergence Zone northwards, the heating of the Tibetan plateau and the position of the tropical easterly jet stream over peninsular India are the other elements of the mechanism.

The four seasons

SeasonMonthsMain features
WinterDecember to FebruaryClear skies, low humidity, rain in the north-west from western disturbances and in Tamil Nadu from the retreating monsoon
SummerMarch to MayRising temperature, the loo in the northern plains, local storms such as Kal Baisakhi and mango showers
South-west monsoonJune to SeptemberThe rainy season, about three-quarters of the annual rainfall, with breaks in the monsoon
Retreating monsoonOctober to NovemberOctober heat, cyclones on the eastern coast, north-east monsoon rain in Tamil Nadu

The south-west monsoon normally reaches Kerala about the first of June, the burst of the monsoon. It then advances in two branches, the Arabian Sea branch and the Bay of Bengal branch, which meet over the north-western plains. The Bay branch is deflected westwards by the Himalaya and moves up the Ganga valley, which is why rainfall in the plains falls from east to west. The monsoon begins to withdraw from north-western India in early September and leaves the southern peninsula by December. During the retreat the winds blow from land to sea, pick up moisture over the Bay of Bengal and give the Coromandel coast of Tamil Nadu its main rainfall, called the north-east or retreating monsoon.

How rainfall is distributed

The average annual rainfall of India is about 125 centimetres, but the distribution is very uneven. Mawsynram and Cherrapunji in the Khasi hills of Meghalaya receive the heaviest rainfall in the country because the funnel shaped hills force the moist Bay branch to rise. The windward side of the Western Ghats, the coastal plain of Kerala and Karnataka, the north-eastern states and the sub-Himalayan belt of West Bengal get over 200 centimetres. The Deccan plateau east of the Ghats and eastern Rajasthan get between 60 and 100 centimetres because they lie in the rain shadow. Western Rajasthan, the Kutch region of Gujarat and the cold desert of Ladakh get under 60 centimetres. A line joining places of equal rainfall on a map is called an isohyet, as a line of equal pressure is an isobar and a line of equal temperature an isotherm.

Local storms and winds

  • Loo: a hot, dry and strong afternoon wind of the northern plains in May and June, which can cause heat stroke.
  • Kal Baisakhi or Norwesters: violent evening thunderstorms of West Bengal, Bihar, Jharkhand and Assam in the pre-monsoon months, useful for jute and rice.
  • Mango showers: pre-monsoon showers in Kerala and coastal Karnataka that help mangoes ripen.
  • Blossom showers or cherry blossom: pre-monsoon showers in Karnataka that help the coffee flowers bloom.
  • Bardoli Chheerha: the name given to pre-monsoon showers in Assam.
  • October heat: the oppressive, humid weather of the retreating monsoon in the northern plains.

Western disturbances, El Nino and La Nina

Western disturbances are low pressure systems that form over the Mediterranean region and travel eastwards with the westerly jet stream. They bring winter rain and snow to Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana and western Uttar Pradesh, and that rain is valuable for the rabi crop, especially wheat. El Nino is the periodic warming of the surface water of the eastern and central Pacific Ocean off the coast of Peru; it usually weakens the Indian monsoon and is associated with deficient rainfall. La Nina is the opposite, cooler than normal Pacific water, and is usually associated with a good monsoon. The Indian Ocean Dipole, the difference in surface temperature between the western and eastern Indian Ocean, also affects the strength of the monsoon. Within the season a spell of several dry days is called a break in the monsoon, and it is a break at the wrong moment, rather than the annual total, that ruins a crop.

Exam Point of View

Three kinds of question come from this topic. First, the mechanism: which wind, which pressure belt, which jet stream, which branch of the monsoon. Second, the names of local winds and storms, where Kal Baisakhi, loo, mango shower, blossom shower and Bardoli Chheerha must be matched to their regions. Third, rainfall figures and terms, where isohyet, the wettest place, the rain shadow of the Western Ghats and the rainfall of Rajasthan are asked. The standard traps are giving the south-west monsoon for the winter rain of Tamil Nadu, mixing the isohyet with the isobar, placing the blossom shower in Meghalaya instead of Karnataka, and reversing the effects of El Nino and La Nina.

Important Facts

Climate typeTropical monsoon; monsoon from the Arabic mausim, meaning season
Onset over KeralaAbout 1 June, known as the burst of the monsoon
Branches of the monsoonArabian Sea branch and Bay of Bengal branch
WithdrawalBegins from north-west India in early September
Rainy season shareAbout three-quarters of the annual rainfall in four months
Average annual rainfallAbout 125 centimetres for the country as a whole
Wettest areaMawsynram and Cherrapunji in the Khasi hills, Meghalaya
Driest areasWestern Rajasthan, Kutch and Ladakh, under 60 centimetres
Line of equal rainfallIsohyet
Winter rain of Tamil NaduNorth-east or retreating monsoon, October to December
Winter rain of north-west IndiaWestern disturbances from the Mediterranean region
Local stormsLoo, Kal Baisakhi, mango shower, blossom shower, Bardoli Chheerha
El NinoWarming of the eastern Pacific; usually weakens the monsoon
Break in the monsoonA dry spell within the rainy season

Practice MCQs on this topic

Q1.GeographyAsked in: Uttar Pradesh · 28 Oct, 2023, Shift 1Easy

What causes rainfall on the coastal areas of Tamil Nadu in the beginning of winters?

  1. A.North-Eastern Monsoon
  2. B.Local Air Circulation
  3. C.Temperate Cyclones
  4. D.South-West Monsoon
Show answer

Correct answer: A. North-Eastern Monsoon

Explanation

The correct answer is A, the north-east monsoon. As the monsoon retreats in October and November the wind direction reverses and air moves from the land towards the sea. Crossing the Bay of Bengal it picks up moisture and strikes the Coromandel coast, giving Tamil Nadu and coastal Andhra Pradesh their main rainy season. This is why Tamil Nadu is the one large part of India whose farming calendar depends on winter rather than summer rain.

Option B, local air circulation, produces land and sea breezes that are too small to give a season of rain. Option C, temperate cyclones, are the western disturbances, and they bring winter rain to the north-west of India, not to the far south. Option D, the south-west monsoon, leaves Tamil Nadu dry because the state lies in the rain shadow of the Western Ghats during those months.

Q2.GeographyAsked in: Delhi · 6th Sep 2021, Shift 2Medium

In which state of India is the rain caused by a lightning storm called Cherry Blossom?

  1. A.Gujarat
  2. B.Meghalaya
  3. C.Uttarakhand
  4. D.Karnataka
Show answer

Correct answer: D. Karnataka

Explanation

The correct answer is D, Karnataka. The pre-monsoon thundery showers of Karnataka are called cherry blossom showers or blossom showers because they help the coffee plants of the Kodagu, Chikkamagaluru and Hassan belt to flower. The same family of pre-monsoon showers is called mango showers in Kerala and coastal Karnataka because it helps mangoes ripen, and the two names are often asked together.

Option A, Gujarat, has no such local shower in the standard list. Option B, Meghalaya, is known for the heaviest rainfall of the country at Mawsynram and Cherrapunji, but that rain comes from the Bay of Bengal branch of the monsoon. Option C, Uttarakhand, receives winter precipitation from western disturbances and monsoon rain in summer, and neither is called a blossom shower.

Q3.GeographyAsked in: SSC GD Constable · 10 Jan 2023, Shift 4Medium

In India, during October-November, with the apparent movement of the sun towards the south, the ______ over the northern plains becomes weaker.

  1. A.Upper level trough
  2. B.Monsoon trough
  3. C.Lee trough
  4. D.Inverted trough
Show answer

Correct answer: B. Monsoon trough

Explanation

The correct answer is B, the monsoon trough. The monsoon trough is the belt of low pressure that lies across the northern plains during the rainy season and guides the depressions that bring rain. As the sun appears to move south of the equator after the September equinox, the land cools, the low pressure weakens and the trough is replaced by high pressure. That retreat of the trough is what is called the withdrawal or retreat of the monsoon, and it begins from north-west India in early September.

Option A, an upper level trough, belongs to the upper air circulation and is not the feature described here. Option C, a lee trough, forms on the sheltered side of a mountain and is a local feature. Option D, an inverted trough, is a name used for a monsoon trough that extends into the Bay of Bengal in a particular shape, not the plains feature that weakens in October.

Q4.GeographyAsked in: Madhya Pradesh · MPPSC General Studies 2015 Official PapeEasy

The line joining the areas having the same rainfall is called:

  1. A.Isobar
  2. B.Isohyet
  3. C.Isotherm
  4. D.Isohaline
Show answer

Correct answer: B. Isohyet

Explanation

The correct answer is B, isohyet. An isohyet is a line drawn on a map through all the places that receive the same amount of rainfall in a given period. Rainfall maps of India are drawn with isohyets, and the crowding of these lines along the Western Ghats shows how sharply rainfall falls from the windward coast to the rain shadow of the plateau.

Option A, an isobar, joins places of equal atmospheric pressure and is used on weather charts to locate depressions and anticyclones. Option C, an isotherm, joins places of equal temperature and is used on temperature maps. Option D, an isohaline, joins places of equal salinity and belongs to the study of the oceans. All four terms carry the Greek prefix iso, meaning equal, and examiners rely on a candidate confusing them.

Q5.GeographyAsked in: SSC CPO · 10 Nov 2022, Shift 3Hard

Which of the following pairs of type of climate and area is NOT correct? I. Semi-arid steppe climate - Punjab. II. Monsoon with dry summer - Coromandel coast of Tamil Nadu.

  1. A.Only I
  2. B.Neither I nor II
  3. C.Only II
  4. D.Both I and II
Show answer

Correct answer: B. Neither I nor II

Explanation

The correct answer is B, neither I nor II, which means that both the pairs given are correct and none of them is wrong. In the Koeppen classification as applied to India, the semi-arid steppe climate marked BShw covers parts of Punjab, Haryana, western Uttar Pradesh and the drier interior of the peninsula, where rainfall is low but not as low as in a true desert. The monsoon type with a dry summer, marked As, covers the Coromandel coast of Tamil Nadu, which stays dry in the south-west monsoon months and receives its rain from the retreating monsoon in winter.

Options A and C each reject one of the two correct pairs, and option D rejects both. The trap lies in expecting every statement in such a question to contain an error.

Q6.GeographyEasy

The south-west monsoon normally reaches the coast of Kerala on about which date?

  1. A.1 April
  2. B.1 May
  3. C.1 June
  4. D.1 July
Show answer

Correct answer: C. 1 June

Explanation

The correct answer is C, 1 June. The south-west monsoon normally sets in over the Kerala coast about the first of June, and the sudden heavy downpour that marks its arrival is called the burst of the monsoon. From Kerala it advances in two branches, one over the Arabian Sea and one over the Bay of Bengal, covering Mumbai by about the tenth of June and the whole country by about the middle of July.

Option A, the first of April, falls in the hot weather season when the land is only beginning to heat. Option B, the first of May, is still the season of pre-monsoon showers such as mango showers and Kal Baisakhi. Option D, the first of July, is far too late, because by then the monsoon has already covered most of the country and the plains are in full rain.

Q7.GeographyEasy

Which place in India receives the highest average annual rainfall?

  1. A.Mawsynram in Meghalaya
  2. B.Agumbe in Karnataka
  3. C.Amboli in Maharashtra
  4. D.Pasighat in Arunachal Pradesh
Show answer

Correct answer: A. Mawsynram in Meghalaya

Explanation

The correct answer is A, Mawsynram in Meghalaya. Mawsynram lies in the Khasi hills, and the neighbouring Cherrapunji, now called Sohra, stands close behind it. The Bay of Bengal branch of the monsoon is funnelled into the wedge shaped valleys of these hills and is forced to rise sharply, so the moisture is wrung out of it and the rainfall is the heaviest recorded in the country.

Option B, Agumbe in the Western Ghats of Karnataka, is called the Cherrapunji of the south and is very wet, but it receives less than Mawsynram. Option C, Amboli in Maharashtra, is another heavy rainfall station of the Ghats but stands lower still. Option D, Pasighat in Arunachal Pradesh, records high rainfall on the Himalayan foothills without reaching the Khasi hills figures.

Q8.GeographyMedium

The violent pre-monsoon evening thunderstorms of West Bengal and Assam are known as:

  1. A.Loo
  2. B.Kal Baisakhi
  3. C.Mango shower
  4. D.Blossom shower
Show answer

Correct answer: B. Kal Baisakhi

Explanation

The correct answer is B, Kal Baisakhi. These are the violent evening thunderstorms of the months before the monsoon in West Bengal, Bihar, Jharkhand and Assam, and the name means the calamity of the month of Baisakh because the squalls can flatten huts and trees. They are also called Norwesters from the direction they come from, and in Assam the same showers are called Bardoli Chheerha. Their rain is useful for tea, jute and rice.

Option A, the loo, is not a storm at all but a hot, dry wind that blows over the northern plains in the afternoons of May and June. Option C, mango showers, are pre-monsoon showers of Kerala and coastal Karnataka that help mangoes ripen. Option D, blossom showers, are the pre-monsoon showers of Karnataka that help coffee to flower.

Q9.GeographyMedium

The winter rainfall of Punjab, Haryana and western Uttar Pradesh is caused by:

  1. A.The retreating monsoon
  2. B.Tropical cyclones of the Bay of Bengal
  3. C.Western disturbances
  4. D.The Arabian Sea branch of the south-west monsoon
Show answer

Correct answer: C. Western disturbances

Explanation

The correct answer is C, western disturbances. These are low pressure systems, that is temperate cyclones, which form over the Mediterranean and the Caspian region and travel eastwards with the westerly jet stream. On reaching north-west India in winter they give light rain in the plains, called mahawat, and snow in the western Himalaya. This small amount of rain is very valuable for the rabi crop, above all for wheat.

Option A, the retreating monsoon, gives its rain to Tamil Nadu and the south-eastern coast in October to December. Option B, the tropical cyclones of the Bay of Bengal, strike the eastern coast, mainly in the pre-monsoon and post-monsoon months. Option D, the Arabian Sea branch, belongs to the summer monsoon and brings no winter rain at all.

Q10.GeographyEasy

El Nino, which is usually linked with a weak Indian monsoon, refers to the warming of the surface waters of which ocean?

  1. A.The Atlantic Ocean
  2. B.The Pacific Ocean
  3. C.The Indian Ocean
  4. D.The Arctic Ocean
Show answer

Correct answer: B. The Pacific Ocean

Explanation

The correct answer is B, the Pacific Ocean. El Nino is the periodic warming of the surface water of the central and eastern Pacific off the coast of Peru and Ecuador, and the name, meaning the child, was given by fishermen because it appears around Christmas. The warm water shifts the belt of rising air and rainfall eastwards, away from the Indian region, so an El Nino year is often a year of deficient monsoon rainfall in India. La Nina is the opposite phase, with cooler than normal water, and usually goes with a good monsoon.

Options A, C and D name the wrong oceans. The Indian Ocean has its own pattern, the Indian Ocean Dipole, which also affects the monsoon, but El Nino is a Pacific phenomenon.

Frequently Asked Questions

Why does Tamil Nadu get rain in winter and not in the south-west monsoon?

The Coromandel coast lies in the rain shadow of the Western Ghats when the south-west monsoon blows, so the Arabian Sea branch has already lost its moisture before it crosses to the east. During the retreat of the monsoon in October and November the winds blow from land to sea, gather moisture over the Bay of Bengal and strike the coast, giving Tamil Nadu its main rainy season, called the north-east or retreating monsoon.

What is a break in the monsoon?

A break is a spell of several dry days in the middle of the rainy season, caused by the shifting of the monsoon trough. Rain stops over the plains while the foothills and the eastern coast may still get showers. Long breaks at the sowing or flowering stage damage crops even in a year whose total rainfall is normal, which is why the distribution of rain matters more than the total.

What is the difference between an isohyet, an isobar and an isotherm?

All three are lines drawn on a map joining places with the same value of a weather element. An isohyet joins places of equal rainfall, an isobar joins places of equal atmospheric pressure and an isotherm joins places of equal temperature. An isohaline joins places of equal salinity in the sea. Examiners ask this as a one-line match, so the four terms should be learnt together.

How do El Nino and La Nina affect India?

El Nino is an abnormal warming of the surface water of the central and eastern Pacific Ocean, and it shifts the rising air and the rain belt away from the Indian region, so monsoon rainfall is usually below normal. La Nina is the cooling of the same waters and is usually linked with a normal or above normal monsoon. The link is a tendency and not a rule, since the Indian Ocean Dipole and other factors also act on the season.

Why is north India warmer in winter than other places on the same latitude?

The Himalaya stands as a wall across the north and blocks the extremely cold winds that blow out of Central Asia in winter. The mountains also hold the monsoon winds within the subcontinent in summer so that they shed their rain here. Without this barrier the northern plains would have a much colder winter, like places at the same latitude in western and central Asia.

Sources

  • Contemporary India II (Class X), chapter on climate — NCERT
  • India: Physical Environment (Class XI), chapter on climate — NCERT
View all