What are the different seasons in India? How do they affect the crop pattern? What do you mean by Loo? Read the article to know more about Seasons in India.
The best way to define India’s climate is in terms of a yearly seasonal cycle. The cold weather season, the hot weather season, the southwest monsoon season, and the retreating monsoon season are the four seasons, according to meteorologists.They are explained below.
The Winter Season or Cold Weather
- Mid-December through mid-March is considered the Winter Season.
- South of the equator is where the sun appears to be travelling.
- This season is marked by clear skies, pleasant weather, cold and gentle northeast trade breezes, low temperatures, low humidity, and a wide variety of temperatures.
- Particularly during the winter months in the interior of the nation, the diurnal temperature variation is incredibly wide.
- The 20°C isotherm and the Tropic of Cancer are nearly parallel.
- To the south of this isotherm, temperatures are higher than 20 °C. There is no distinct winter climate in this area.
- In some areas of Tamil Nadu and Kerala, the temperature frequently reaches 30 degrees.
- The north has distinct winter weather with an average temperature below 21°C.
- The Gangetic plains have a mean minimum temperature of about 10°C, compared to a mean minimum of about 5°C in north-western India.
- India’s coldest place is the Dras Valley in Kashmir. The lowest temperature ever at Dras was -45°C in 1908.
Pressure During the Winter
- High air pressure is present across a significant portion of north-western India due to low temperatures and divergence caused by the STJ (SubTropical Jet Streams) ridge.
- The pressure in South India is lower than it is in the rest of the nation.
- From a north-westerly high-pressure area to a south-easterly low-pressure area, the winds start to blow.
- The low-pressure gradient and low wind velocity are related.
- The pressure gradient and physiography determine the wind’s route.
Western Upheavals during the Winter
- In northwest and northern India, the arrival of western disturbances frequently interrupts a period of favorable weather.
- In Rajasthan, Punjab, and Haryana, they intensify.
- They go through the sub-Himalayan belt in an easterly direction, eventually arriving in Arunachal Pradesh.
- They produce modest rain in the Indus Ganga lowlands and snow in the Himalayan region.
- After the disturbance passed, extensive fog and cold waves arrived and caused the minimum temperature to drop by 5° to 10°C.
- Visibility is drastically reduced by fog, which is very problematic when traveling.
Also read: Unseasonal Rains in India
Tropical cyclones during the winter
- During this time of year, tropical cyclone activity is at its lowest.
- The low sea surface temperature and the ITCZ’s furthest south egress are to blame for this ( Intertropical Convergence Zone).
- Tamil Nadu is battered by storms with origins in the Bay of Bengal, which produce a lot of rain.
- From the southern peninsula, some of them span the Arabian Sea.
- There aren’t many storms that develop in the Arabian Sea and move north or west.
Precipitation in Winter Season
- The receding winter monsoons take up moisture while crossing the Bay of Bengal, resulting in winter rainfall in Tamil Nadu, south Andhra Pradesh, south-east Karnataka, and south-east Kerala (Usually in the first weeks of November).
- The largest seasonal rainfall of roughly 75 cm occurs between October and December.
- The majority of it takes place in Andhra Pradesh’s surrounding regions and along the southern coast of Tamil Nadu. After then, it progressively goes down.
- The western disturbances also bring a little rain to northwest India.
- Rainfall steadily decreases from the north and northwest to the east (it is the opposite in the rainy season).
- In the northeastern region of India, it rains during the winter.
The Summer or Hot Weather Season
- Mid-March through May is considered the Summer Season.
- This season is characterized mostly by high temperatures and little humidity.
- Pre-monsoon season is another name for the hot weather season.
The summertime temperature
- There is a wide range of sun insolation because the sun appears to wander between the equator and the Tropic of Cancer.
- The southern regions of the nation are considerably warmer in March and April, while June brings greater temperatures to north India.
- The country’s southern regions record the highest temperatures in March (40–45°C).
- The highest temperature ever recorded in Madhya Pradesh’s northern regions was around 45°C in April.
- The hottest month is May when Rajasthan has had temperatures as high as 48°C.
- June is when temperatures are at their maximum in Punjab and Haryana.
- The two highest recorded temperatures are 50.6°C on June 14, 1935, at Ganganagar, and 50.5°C on May 10, 1956, in Alwar.
- Just before the onset of the southwest monsoon, the highest temperatures are recorded (late May).
- The temperature range throughout the day is likewise extremely wide. The mercury may rise as high as 18°C in some places.
- Maximum summer temperatures are noticeably lower in the coastal and southern peninsular regions due to the cooling impact of the sea.
- Temperatures on the west coast are typically cooler than those on the east coast due to the predominance of westerly winds.
- The temperatures at sea and on land are very different.
- Heat waves are common during this time of year in Northern and Central India.
Also read: Mechanism of Indian Monsoon
Pressure During the Summer
- The country’s air pressure is low because of the heat.
- On the other side, a strong dynamically driven divergence delays the arrival of the southwest monsoons over northwestern India.
Winds in the Summer
- Beginning in the winter, the winds‘ velocities and directions drastically alter.
- Generally speaking, the wind is varied and light.
- Iran, Baloch, and Thar deserts are the source of loo winds.
- High temperatures in northwest India cause a sharp pressure gradient in May and June.
- A fierce, hot, dusty breeze called loo blows.
- Around 9.00 a.m., the loo typically begins to blow, gradually builds in strength, and peaks in the afternoon.
- It can linger for days and blows at a consistent speed of 30 to 40 km/h.
- Strong dust storms brought on by convective events are known locally as andhis (blinding storms).
- They move like a wall of solid sand and dust.
- The visibility is only a few meters and the wind is regularly between 50 and 60 kilometers per hour.
- Dust storms are common in Rajasthan, Haryana, Punjab, Jammu and Kashmir, Delhi, Uttar Pradesh, Bihar, and Madhya Pradesh.
Frontal thunderstorms throughout the summer
- Strong convectional movements brought on by the westerly jet stream are what cause thunderstorms to form in the eastern and northern areas of the country.
- Westerly winds typically pick them up over the Chota Nagpur plateau and carry them to the east.
- The states with the highest frequency of thunderstorms include Assam, Arunachal Pradesh, Nagaland, Mizoram, Manipur, Tripura, Meghalaya, West Bengal, and the surrounding regions of Odisha and Jharkhand.
Summertime Nor’westers and Thunderstorms
- Norwesters sometimes referred to as squalls, are storm systems that typically develop in West Bengal and the neighboring states of Jharkhand, Odisha, and Assam.
- With squall speeds reaching from 60 to 80 km/h, they are often violent.
- Sometimes, showers are accompanied by golf ball-sized hailstones.
- They kill people and wreak havoc on cattle, standing crops, trees, buildings, and other structures.
- They do, however, occasionally come in handy for growing rice, jute, and tea.
- In Assam, these storms are known as “Barodoli Chheerha.”
- Since these storms typically occur in the month of Vaisakh (mid-March to mid-April), they are referred to locally as Kalabaisakhis, or “black storms,” or “a mass of dark clouds of Vaishaka.
Convectional storms throughout the summer
- In Kerala (Mango Showers), nearby Karnataka (Blossom Showers), and Tamil Nadu in the south, thunderstorms are possible.
- These thunderstorms mostly happen at night and in the evening.
Western Disturbances in the Summer
- They become less frequent and intense as the summer goes on.
- Four, three, and two western disturbances swept over northwest India in the months of March, April, and May, respectively.
- In the upper altitudes of the Himalayas, they cause snowfall.
Tropical cyclones during the summer
- Tropical cyclones are born in the Arabian Sea and the Bay of Bengal.
- A few cyclones develop in the Bay of Bengal during March, although they have no impact on mainland of India.
- The number of cyclones beginning in May more than doubles that in April, and their frequency rises sharply in April.
- About three-fourths of tropical cyclones are created in the Bay of Bengal, with the remainder occurring in the Arabian Sea.
- In contrast to those that originate in May, the majority of the depressions that form in April are born north of 10°N.
- This season, the bulk of storms initially go west or northwest before turning back toward the northeast and striking Bangladesh and Myanmar’s Arakan Coast.
- Only a few reach the Indian coast, while the majority float away.
- Tropical storms are predicted to make landfall in May throughout India’s whole east coast, as well as in Bangladesh’s coastal regions and Myanmar’s Arakan Coast.
- Numerous of them cause major loss of life and property and are highly serious.
- In May, large storm systems develop in the Arabian Sea between 7° and 12° N latitudes.
- Most of them drift away from the Indian coast in a northerly direction and disappear into the ocean.
- Near the Indian shore, few can be discovered. They go northeast and eventually land on India’s west coast.
Rainfall during the summer months
- Rain doesn’t fall every day throughout this season (only one percent of the annual rainfall).
- The northern regions of the country receive little rain as a result of dust storms.
- The most frequent type of precipitation in Kashmir, which is brought on by disturbances in the west, is snowfall.
- The northwest sends rain to Assam, West Bengal, and Odisha. The rainfall is intense.
- The rainstorms that spring brings are caused by northwesterly.
- Because it is so helpful for the growth of tea, jute, and rice, this little bit of rain in Assam is known as “tea showers.”
- The coastal regions of Kerala and Karnataka receive rain due to thunderstorms.
- Due to their enormous benefits to the mango crop, these showers are known as “mango showers” in Tamil Nadu and Andhra Pradesh.
- Karnataka refers to them as cherry blossoms because of the effect they have on coffee farms.
The Rainy season or Southwest Monsoon
- June to September is considered the Rainy Season.
- The significant increase in temperature across the northwest plains in May has intensified the low-pressure conditions there.
- By early June, they are strong enough to draw trade winds from the Indian Ocean that are native to the Southern Hemisphere.
- These trade winds from the southeast pass via the Arabian Sea and the Bay of Bengal after crossing the equator, only to be caught up in the airflow over India.
- As they cross the heated equatorial currents, they carry a lot of moisture with them.
- After crossing the equator, they proceed southwestward. As a result, the southwest monsoon is named.
Bursts of the Southwest monsoon
- The southwest monsoon season has a sudden onset of rain.
- The initial downpour has the impact of sharply decreasing the temperature.
- When the monsoons “break” or “burst,” winds carrying moisture accompanied by ferocious thunder and lightning, occur.
- The monsoon may begin in the first week of June in the coastal regions of Kerala, Karnataka, Goa, and Maharashtra while it may begin in the first week of July in the interior.
- The daily temperature drops from mid-June to mid-July by 5°C to 8°C.
- The southwesterly direction of these winds as they reach the land is modified by the relief and thermal low pressure over northwest India.
- As the mainland approaches, the monsoon splits into two branches:
- Branch of the Arabian Sea
- Branch of the Bay of Bengal
The Retreating Monsoon or the Cool Season
- In October and November, monsoons are known to retreat.
- The Ganga plain’s low-pressure trough starts to travel southward towards the end of September in reaction to the sun’s southerly march, which weakens the southwest monsoon.
- Western Rajasthan is free of the monsoon by the first week of September.
- It will have left Rajasthan, Gujarat, the Western Ganga plain, and the Central Highlands by the end of the month.
- In the southern half of India, the monsoon is retreating.
- By early October, the low-pressure system had moved across the northern portions of the Bay of Bengal, and by early November it is over Karnataka and Tamil Nadu.
- By the middle of December, the area of low pressure will be entirely gone from the Peninsula.
- The southwest monsoon season is ending as the weather becomes clearer and warmer. The soil is still drenched.
- The high warmth and humidity make the weather uncomfortable. The term “October heat” is used to describe this.
- The monsoon in the Northern Half of India is Withdrawing
- In the second half of October, temperatures start to rapidly fall, particularly in northern India.
- While the eastern section of the Peninsula has rained during the retreating monsoon, the weather in north India remains dry.
- In this region, October and November are the wettest months of the year.
- Cyclonic depressions that develop over the Andaman Sea and travel to the eastern coast of the southern Peninsula are associated with the arrival of the rainy season.
Effects of the Monsoon’s Reversal
- These tropical cyclones pose a serious threat.
- The crowded deltas of the Godavari, Krishna, and Kaveri rivers are their favored prey.
- These cyclones wreak havoc in this region every year.
- There have also been cyclonic storms that have impacted the shores of West Bengal, Bangladesh, and Myanmar.
- Most of the rainfall on the Coromandel coast is caused by these depressions and cyclones.
- Such cyclonic storms are less common in the Arabian Sea.
Also read: World Climate: Types and its Characteristics
Compared to a one-season climate, a four-season climate offers significantly more chances for life. The four seasons each give a different outlook on life and are unique in their own right. Every season brings with it a fresh slate of activities and climatic circumstances that are also advantageous to the preservation of the Earth’s features and the well-being of living things, particularly the flora and wildlife.
Article Written by: Atheena Fathima Riyas