Withdrawal of the Monsoon : Geography
Even as the withdrawal of the monsoon begins to take place, there is still a lot to learn from the way it behaves. Under its influence, a complex pattern of winds and ocean currents can be established which affects cloud behavior and allows us to predict the onset of the northeast monsoon season over the Bay of Bengal.
This understanding will allow us to predict monsoon cyclones, tropical cyclones and depressions which develop over this time period. The Seasons – 4 main seasons can be identified in India:
- The cold weather season (Winter)
- The hot weather season (Summer)
- The advancing monsoon (Rainy Season)
- The retreating monsoon with some regional variations (Transition Season)
The Cold Weather Season (Winter)
Winter, the coldest season of the year, comes between autumn and spring. It is associated with plunging temperatures and icy weather, but its impact and timing change according to location. The farther an area lies from the equator, the colder temperatures it experiences.
Winter begins from mid-November in northern India and stays till February. December and January are the coldest months in the northern part of India.
The temperature decreases from south to the north. The weather is marked by clear sky, low temperatures and low humidity and feeble, variable winds. This season is extremely important for the cultivation of ‘rabi’ crops.
During the cold season, the days are warm and nights are cold. When temperature decreases, frost is commonly experienced in Northern IndiaThe cold season in most parts of the country is the dry season as northeast trade winds blow from land to sea. Many cyclonic disturbances occur over northern India during this time.
The Hot Weather Season (Summer)
From March to May, hot weather season is observed in India. The summer months experience rising temperature and falling air pressure in the northern part of the country.
A striking feature of the hot weather season is the ‘loo’. Loo is the strong, gusty, hot, dry winds blowing during the day over the north and northwestern India.
Towards the close of the summer season, pre-monsoon showers come which help in the early. Ripening of mangoes, and are often referred to as ‘mango showers’.
During this period, the global heat belt shifts towards north because of the apparent northward movement of the sun. This is also the season of localized thunderstorms; accompanied by violent winds, torrential downpours, and hail.
Advancing Monsoon (The Rainy Season)
The advancing monsoon occurs in the month of June, July, August and September. Advancing monsoon brings a major change in the weather conditions.
At the beginning of the monsoon, Western Ghats get very heavy rainfall. North east part of India gets the maximum amount of rainfall because of the advancing monsoon.
The monsoon winds cover the country in about a month. Mawsynram in the southern ranges of the Khasi Hills receives the highest average rainfall in the world.
A phenomenon associated with the monsoon is its tendency to have ‘breaks’ in rainfall. These breaks in monsoon are related to the movement of the monsoon trough. The trough and its axis keep on moving northward or southward and determine the spatial distribution of rainfall.
The Frequency and intensity of tropical depressions also determine the amount and duration of monsoon rains. The monsoon is known for its uncertainties. The alternation of dry and wet spells vary in intensity, frequency and duration.
Retreating/Post Monsoons (The Transition Season)
October marks the end of monsoon season in India. It is a time when there is transition from hot rainy conditions to cool dry winter season. The retreat of the monsoon is marked by clear skies and rise in temperature.
While day temperatures are high, nights are cool and pleasant. Owing to the conditions of high temperature and humidity, the weather becomes rather oppressive during the day.
This is commonly known as ‘October heat’ In the second half of October, the mercury begins to fall rapidly in northern India.