Seasons of India - The Winter Season or Cold Weather

The Winter Season or Cold Weather

• Northern India's cold weather season begins in mid-November and lasts until February. The coldest months in northern India are December and January.
• During winter season, the tropic of Capricorn, which is far from India, receives the vertical rays of the sun. India thus receives the sun's rays at a low angle, resulting in a cold climate.
• The temperature falls from south to north. The average temperature in Chennai, on the eastern coast, is between 24° and 25° Celsius, while it ranges between 10° and 15° Celsius in the northern plains.
• The days are warm, but the nights are cold. Frost is common in the north, and snowfall occurs on the higher slopes of the Himalayas.
• A weak high-pressure region develops in the north of the country, with light winds blowing out from it. These winds blow through the Ganga valley from the west and northwest, influenced by the relief.
• The cold weather season is highlighted by bright skies, pleasant weather, light northerly winds, low humidity, and significant daytime temperature changes.

1. Temperature 

• January is typically the coldest month during the winter season. During the winter months, the temperature in the Indian subcontinent remains quite low. Temperatures drop from south to north. The average maximum temperature in January in Thiruvananthapuram is 31°C, 26°C in Calicut, 24°C in Chennai, 16 °C in Varanasi, and 10°C in Jammu. The temperature at night in the Gangetic Plains ranges from 2.5°C to 17.5°C. Temperatures in the higher reaches of the Himalayas fall below freezing point. Dras Valley, near Kargil in Kashmir, has a minimum temperature of -45°C. It is India's coldest location.
• The extreme cold in north India during this season is caused by the following factors:
  a. In the month of February, the cold winds from the Caspian Sea and Turkmenistan bring cold wave over the northwestern parts of India;
  b. Punjab, Haryana and Rajasthan experience continental type of climates as they are located far away from the sea to experience its moderating influence;
  c. The snowfall in the nearby Himalayan ranges creates a cold wave situation. 
• The average temperature in Peninsular India ranges from 20°C to 25°C, and there is no clearly defined cold weather season. Because of the moderating influence of the sea and proximity to the Equator, coastal areas rarely experience seasonal changes in temperature distribution patterns. For example, the average maximum temperature in Thiruvananthapuram in June is 29.5°C, while it is 31°C in January.

2. Pressure

• The weather in this season is characterised by weak high pressure conditions over the north-western part of the plain. This is because of the oblique rays of the sun which reach the subcontinent as the sun moves to the Southern Hemisphere. 
• The North-East Trade Winds dominate the country during this season. Because these winds blow from land to sea, most of the country is in dry season. When these winds pass over the Bay of Bengal, they pick up moisture and cause some rain on the Coromandel Coast. These winds are known as the North-East Monsoon Winds because they blow from north-east to south-west.

3. Temperate Cyclones (Western Disturbances)

• A characteristic feature of the cold weather season is the inflow of depressions from the west and the north-west. These low pressure systems, called the western disturbances, originate in West Asia and the regions near the Mediterranean Sea. During the winter, they migrate eastward through Iran and Pakistan, eventually arriving in India. They bring much-needed winter rains and snowfall to the plains and mountains. Each winter, India is hit by four or five such depressions on an average. They are most active between the months of December and February. Although the amount of winter rainfall is less, it is critical for the cultivation of rabi crops.

4. Rainfall 

• During the winter season, most parts of India receive no rain. This is because the winter monsoons have little humidity and the possibility of rain from them decreases due to anti-cyclonic circulation on land. However, some areas do receive rainfall during the winter season. These are their names:
  a. Central parts of India and northern parts of the Peninsula get occasional rainfall in winter.
  b. Rainfall is caused by weak temperate cyclones from the Mediterranean Sea in Delhi, Haryana, Punjab, and western Uttar Pradesh. Even though the amount of rain is small, it is very beneficial to the rabi crops.
  c. During the winter months, rain falls in the north-eastern part of India. During the winter, Arunachal Pradesh and Assam receive 25mm to 50mm of rain.
  d. During the months of October and November, the North-East Monsoon picks up moisture as it crosses the Bay of Bengal, bringing torrential rains to the coast of Tamil Nadu and the southern tip of Andhra Pradesh.