India's climatic conditions are best described in terms of an annual seasonal cycle. According to meteorologists, the four seasons are the cold weather season, the hot weather season, the southwest monsoon season and the retreating monsoon season.This article will explain to you about these Seasons in India which will be helpful in preparing Geography for the UPSC Civil service exam.

The Cold Weather or Winter Season

• The Winter Season is from mid December to mid-March.
• The apparent path of the sun is south of the equator.
• Clear skies, pleasant weather, cool and slow north-east trade winds, low temperature, low humidity, wide temperature range accompany this season.
• The diurnal temperature range is extremely wide, especially in the country's interior during winter.

Temperature in Winter Season

• The 20°C isotherm runs roughly parallel to the Tropic of Cancer.
• Temperatures are above 20°C to the south of this isotherm. There is no clearly defined winter weather here.
• Temperatures in some parts of Kerala and Tamil Nadu regularly reach 30°C.
• The average temperature in the north is below 21°C, and the winter weather is distinct.
• North-west India has a mean minimum temperature of about 5°C, while the Gangetic plains have a mean minimum temperature of about 10°C.
• The Dras Valley in Kashmir is India's coldest location. In 1908, the lowest temperature recorded at Dras was – 45°C.

Pressure in Winter Season

• Low temperatures, combined with divergence induced by the STJ ( SubTropical Jet Streams ) ridge, results in high air pressure over large parts of north-west India.
• South India has a lower pressure than the rest of the country.
• The winds begin to blow from a north-westerly high pressure area to a south-easterly low pressure area.
• Because of the low pressure gradient, the wind velocity is low.
• The wind's path is determined by the pressure gradient and physiography.

Western Disturbances in Winter Season

• The inflow of western disturbances frequently breaks the spell of good weather in northwestern and northern India.
• They become more intense in Rajasthan, Punjab, and Haryana.
• They migrate eastward through the sub-Himalayan belt, eventually reaching Arunachal Pradesh.
• In the Indus Ganga plains, they cause light rain, while in the Himalayan belt, they cause snowfall.
• Following the disturbance's passage, widespread fog and cold waves set in, lowering the minimum temperature by 5° to 10°C below normal.
• Fog reduces visibility and makes transportation extremely inconvenient.

Tropical Cyclones in Winter Season

• Tropical cyclone activity is at its lowest during this season.
• As the season progresses, the frequency of tropical cyclones decreases.
• This is due to the low sea surface temperature and the farthest south exit of the ITCZ ( Intertropical Convergence Zone).
• Storms that originate in the Bay of Bengal hit Tamil Nadu, bringing heavy rain.
• Some of them cross the Arabian Sea from the southern peninsula.
• Few storms form in the Arabian Sea and travel to the north or west.

Precipitation in Winter Season

• While crossing the Bay of Bengal, the retreating winter monsoons pick up moisture and cause winter rainfall in Tamil Nadu, south Andhra Pradesh, south-east Karnataka, and south-east Kerala (Usually in the first weeks of November).
• Between October and December, the highest seasonal rainfall of about 75 cm occurs.
• The majority of it occurs along Tamil Nadu's south-eastern coast and adjacent areas of Andhra Pradesh. Following that, it gradually decreases.
• In northwest India, the western disturbances also bring a little rain.
• From the north and north-west to the east, the amount of rainfall gradually decreases (it is the opposite in the rainy season).
• During the winter, rainfall occurs in the northeastern part of India.

The Hot Weather Season or Summer Season

• The Summer Season is from mid-March to May.
• The key characteristics.of this season include high temperature and low humidity.
• The hot weather season is sometimes referred to as the pre-monsoon period.

The temperature in Summer Season

• Due to the apparent movement of the sun between the equator and the Tropic of Cancer, there is a huge range of sun insolation.
• In March and April, the southern parts of the country are noticeably warmer, whereas north India experiences higher temperatures in June.
• The southern parts of the country experience the highest temperatures (40-45°C) in March.
• In the northern parts of Madhya Pradesh, the highest temperature of around 45°C was recorded in April.
• The hottest month is May, when temperatures as high as 48°C have been recorded in Rajasthan.
• Punjab and Haryana experience the highest temperatures in June.
• The highest recorded temperatures are 50.5°C in Alwar on May 10, 1956, and 50.6°C in Ganganagar on June 14, 1935.
• The highest temperatures are measured just before the southwest monsoons arrive (late May).
• The diurnal temperature range is also quite large. In some areas, temperatures may reach as high as 18°C.
• Due to the cooling effect of the sea, maximum summer temperatures are comparatively lower in the coastal and southern peninsular regions.
• Because of the prevailing westerly winds, temperatures on the west coast are generally cooler than those on the east coast.
• Temperatures on land and at sea differ dramatically.
• In this season, heat waves hit the northern and central parts of India.

• The majority of the heat waves occur in Rajasthan, Punjab, and Haryana (location far away from the sea). They spread across Uttar Pradesh and Bihar from here.
• Strong northwesterly winds (due to a strong divergence in north-west India) with a long land journey over hot regions quash the sea breeze's progress along the eastern coastal belt, causing heat waves in Odisha and Andhra Pradesh.
• By the end of April, heat waves arrive and their frequency peaks in May.
• They last until the southwest monsoon arrives.
• Heatwaves usually last four to five days.
• Heat waves, on the other hand, are uncommon on the peninsular south of 13°N latitude due to the maritime conditions that prevail there.

Pressure in Summer Season

• Due to the hot weather, atmospheric pressure is low across the country.
• Strong dynamically induced divergence, on the other hand, prevents the onset of the south-west monsoons over north-west India.

Winds in Summer Season

• The direction and speed of the winds changes dramatically as of winter.
• The wind is generally light and variable.

Loo

• Loo winds originate in the deserts of Iran, Baloch, and Thar.
• High temperatures in northwest India create a steep pressure gradient in May and June.
• Loo blows, which is a hot, dusty, and strong wind.
• Loo usually starts blowing around 9.00 a.m., gradually increases in intensity, and peaks in the afternoon.
• It blows at a constant speed of 30-40 km/h and can last for days.

Andhis

• Strong dust storms caused by convective phenomena are referred to as andhis in the local community (blinding storms).
• They move as if they were a solid wall of sand and dust.
• The wind is frequently between 50 and 60 kilometers per hour, and visibility is reduced to a few meters.
• Rajasthan, Haryana, Punjab, Jammu and Kashmir, Delhi, Uttar Pradesh, Bihar, and Madhya Pradesh are all prone to dust storms.
• They don't last long. The squalls and showers that follow these storms bring the temperature down dramatically for a short time.

Frontal Thunderstorms in Summer Season

• Thunderstorms can be found in the eastern and north-eastern parts of the country due to strong convectional movements caused by the westerly jet stream.
• They usually start over the Chota Nagpur plateau and are carried east by westerly winds.
• Assam, Arunachal Pradesh, Nagaland, Mizoram, Manipur, Tripura, Meghalaya, West Bengal and the adjoining areas of Odisha and Jharkhand have the highest frequency of thunderstorms.

Norwesters and Thunderstorms in Summer Season

• Squalls primarily originate from the northwest in West Bengal and the adjoining areas of Jharkhand, Odisha, and Assam, and are known as norwesters.
• They are frequently violent, with squall speeds ranging from 60 to 80 km/h.
• Hailstones, which can reach the size of a golf ball, sometimes accompany showers.
• They cause havoc on standing crops, trees, buildings, and livestock, and even result in human deaths.
• They are, however, sometimes useful in the cultivation of tea, jute, and rice.
• These storms are known as 'Barodoli Chheerha' in Assam.
• The month of Vaisakh (mid-March to mid-April) is when these storms are most common, and thus they are known locally as Kalabaisakhis, or black storms or a mass of dark clouds of Vaisakha.

Convectional Thunderstorms in Summer Season

• Thunderstorms can be found in Kerala (Mango Showers) and adjoining parts of Karnataka (Blossom Showers) and Tamil Nadu in the south.
• These thunderstorms especially occur during the evenings and nights.

Western Disturbances in Summer Season

• As the summer progresses, their frequency and intensity decrease.
• In March, April, and May, respectively, four, three, and two western disturbances pass through northwestern India.
• They cause snowfall in the Himalayas' higher reaches.

Tropical Cyclones in Summer Season

• The Bay of Bengal and the Arabian Sea are the birthplaces of tropical cyclones.
• In the month of March, a few cyclones form in the Bay of Bengal, but they do not affect India's mainland.
• Their frequency increases dramatically in April, with the number of cyclones originating in May more than doubling that of April.
• The Bay of Bengal produces about three-quarters of tropical cyclones, while the Arabian Sea produces the rest.
• The majority of the depressions that form in April are born south of 10°N, while those that form in May are born north of this latitude.
• The majority of the storms this season move west or north-west at first, but then recurve northeast and hit Bangladesh and Myanmar's Arakan Coast.
• Only a few make it to the Indian coast, while others dissipate over the sea.
• In May, tropical storms are expected to hit the entire east coast of India, as well as Bangladesh's coastal areas and Myanmar's Arakan Coast.
• Many of them are quite serious and result in significant loss of life and property.
• Major storms form in the Arabian Sea between 7° and 12° N latitudes in May.
• The majority of them move north-westerly away from the Indian coast and dissipate in the sea.
• Few are found near the Indian coast. They head north-east, eventually arriving somewhere along India's west coast.

Precipitation in Summer Season

• This season isn't completely devoid of rain (only one percent of the annual rainfall).
• Dust storms bring little rain to the northeastern parts of the country.
• Snowfall is the most common form of precipitation in Kashmir, which is caused by western disturbances.
• In Assam, West Bengal, and Odisha, the northwestern brings rain. Rainfall has a high intensity.
• Spring storm showers are the rainstorms brought on by northwestern.
• In Assam, this small amount of rain is known as tea showers because it is very beneficial for the cultivation of tea, jute, and rice.
• Thunderstorms bring rain to Kerala and Karnataka's coastal areas.
• In Tamil Nadu and Andhra Pradesh, such showers are known as mango showers because they are extremely beneficial to the mango crop.
• They're known as cherry blossoms in Karnataka because of their impact on coffee plantations.

The Southwest Monsoon or Rainy Season

• The Rainy Season is from June to September.
• As a result of the rapid rise in temperature over the northwestern plains in May, the low pressure conditions there have become even more intense.
• They are powerful enough to attract the Southern Hemisphere trade winds coming from the Indian Ocean by early June.
• These southeast trade winds cross the equator and enter the Bay of Bengal and the Arabian Sea, only to become entangled in the air circulation over India.
• They bring a lot of moisture with them as they pass over the equatorial warm currents.
• They travel in a southwesterly direction after crossing the equator. Southwest monsoons are named after this.

Southwest Monsoon Bursts

• The rain begins abruptly during the southwest monsoon season.
• The first rain has the effect of significantly lowering the temperature.
• The "break" or "burst" of the monsoons refers to the sudden onset of moisture-laden winds accompanied by violent thunder and lightning.
• In the coastal areas of Kerala, Karnataka, Goa, and Maharashtra, the monsoon may arrive in the first week of June, while in the interior, it may arrive in the first week of July.
• Between mid-June and mid-July, the daytime temperature drops by 5°C to 8°C.
• The relief and thermal low pressure over northwest India modify the southwesterly direction of these winds as they approach the land.
• The monsoon is divided into two branches as it approaches the landmass:
  • The Arabian Sea branch
  • The Bay of Bengal branch

*To know more about this, click Southwest Monsoon Season

The Retreating Monsoon or Cool Season

• Monsoons are known to retreat in the months of October and November.
• By the end of September, the southwest monsoon gets weakened as the Ganga plain's low pressure trough begins to move southward in response to the sun's southward march.
• By the first week of September, the monsoon leaves western Rajasthan.
• By the end of the month, it will have left Rajasthan, Gujarat, the Western Ganga plain, and the Central Highlands.

Retreating Monsoon in the Southern Half of India

• The low-pressure system covers northern parts of the Bay of Bengal by early October, and it moves over Karnataka and Tamil Nadu by early November.
• The center of low pressure will be completely removed from the Peninsula by the middle of December.
• Clear skies and rising temperatures signal the retreating of the southwest monsoon season. The ground is still wet.
• The weather becomes oppressive as a result of the high temperature and humidity. This is referred to as the 'October heat.'

Retreating Monsoon in the Northern Half of India

• The temperature begins to drop rapidly in the second half of October, especially in northern India.
• The weather in north India during the retreating monsoon is dry, but rain is associated with it in the eastern part of the Peninsula.
• The rainiest months of the year are October and November in this area.
• The rainy season is linked to the passage of cyclonic depressions that originate over the Andaman Sea and make their way to the southern Peninsula's eastern coast.

Effects caused by Retreating Monsoons

• These tropical cyclones are extremely dangerous.
• Their preferred targets are the densely populated deltas of the Godavari, Krishna, and Kaveri rivers.
• Every year, these cyclones devastate this area.
• The coasts of West Bengal, Bangladesh, and Myanmar have also been hit by cyclonic storms.
• These depressions and cyclones are responsible for the majority of the rainfall on the Coromandel coast.
• In the Arabian Sea, such cyclonic storms are less common.

Conclusion

A four-season climate provides far more opportunities for living than a one-season climate. Each of the four seasons offers a different perspective on life and is distinct in its own way. Each season brings with it a new set of activities and climatic conditions which are also beneficial in maintaining the Earth’s features and to the living creatures, especially the flora and fauna.

GS Mains Questions and Model Answers

Q1. Discuss the importance of the monsoon season for India’s economy and agriculture.

Answer: The monsoon season, spanning from June to September, plays a pivotal role in India’s economy, especially in the agricultural sector. Since a large portion of Indian agriculture is rain-fed, the monsoon directly impacts crop production. Crops like rice, cotton, and pulses depend heavily on timely and adequate rainfall. A good monsoon boosts agricultural output, stabilizes food prices, and supports rural employment. On the other hand, irregular monsoons can lead to droughts or floods, disrupting agriculture and affecting the economy. Additionally, industries such as textiles and sugarcane processing rely on agricultural inputs, making the monsoon season critical to their success.

Q2. How do the Himalayas influence the climate and seasons of India?

Answer: The Himalayas play a vital role in shaping the climate of India by acting as a barrier to cold winds from Central Asia, ensuring that northern India remains warmer than other regions at similar latitudes. During winter, they block frigid winds, contributing to relatively mild winters in the Indo-Gangetic plains. The mountains also facilitate the onset of the monsoon by forcing the moist winds to rise, cool, and precipitate, especially on the windward side. The varying topography of the Himalayas also causes regional climatic variations, such as heavy rainfall in the northeastern states and arid conditions in Ladakh.

Q3. Analyze the impact of changing monsoon patterns on the socio-economic landscape of India.

Answer: In recent years, climate change has altered the patterns of the Indian monsoon, resulting in delayed or erratic rainfall. This unpredictability has far-reaching socio-economic impacts. Farmers face uncertainty regarding crop cycles, leading to increased instances of crop failure, rural indebtedness, and migration. Water scarcity has become more prevalent, impacting both agriculture and drinking water supplies. Industries reliant on agricultural outputs also suffer due to production losses. Moreover, extreme weather events such as floods and droughts have increased in frequency, further stressing resources. Addressing these challenges requires improved forecasting, water management strategies, and policies that enhance agricultural resilience.

Previous Year Questions on Seasons in India

1. UPSC CSE 2023

Question. Explain how the Indian monsoon system is influenced by global factors.

Answer: The Indian monsoon system is primarily driven by the differential heating of land and ocean surfaces, but it is also influenced by several global factors. The El Niño–Southern Oscillation (ENSO) phenomenon impacts the strength and onset of monsoons, with El Niño causing reduced rainfall and La Niña enhancing it. The Indian Ocean Dipole (IOD) also plays a crucial role, with a positive IOD phase contributing to increased monsoon rainfall. Other factors, like the Madden-Julian Oscillation (MJO), impact intra-seasonal variability. Changes in Arctic ice and Himalayan snow cover further influence wind patterns, impacting the monsoon’s intensity and distribution.

2. UPSC CSE 2021

Question. Evaluate the significance of winter rains brought by western disturbances in India.

Answer: Western disturbances are critical weather systems originating from the Mediterranean region that bring winter rains to northern India, especially in the states of Punjab, Haryana, and parts of Uttar Pradesh. These disturbances impact the Rabi crop season, particularly the wheat crop, which benefits from timely winter rains. In addition to their agricultural importance, western disturbances also influence regional temperatures, providing respite from extreme cold. However, excessive rainfall can lead to localized flooding and disrupt transportation. The role of these disturbances has become increasingly relevant with changing climatic patterns, as any alteration in their frequency or intensity directly impacts India’s winter agriculture and water availability.