SEASONS IN INDIA

SEASONS IN INDIA
On the basis of monsoonal variations there are four seasons in India.

THE COLD WEATHER SEASON It starts in early December. The mean January temperature in Chennai and Thiruvananthapuram is about 24°-25°C, while in the North­ern Plains it is about 10°-15°C. A high pressure area is developed over the plains in the north-west. Sometimes weather is disturbed by cyclonic depressions which origi­nate over the Mediterranean and travel eastwards and reach north-west India. These western disturbances bring rainfall in Punjab region. The Tamil Nadu coastland also receives rainfall during this season from retreating north­eastern winds.

THE HOT-WET WEATHER SEASON It starts in March and continues upto June. The Inter-Tropical Convergence (ITC) belt shifts from south to north. Along with it moist equatorial air is drawn from the Indian Ocean due to the anticyclone located around Malagasy. The highest tempera­ture in March is about 38°C in the Deccan plateau. In April, Gujarat and Madhya Pradesh become more hot. The day temperature ranges from 38°C to 43°C. It increases upto 48°C in north-west India in May-June.

Due to increase in temperature the air pressure de­creases. A low pressure belt develops by the end of May in Thar desert. Mango showers (pre-monsoon showers) occur in the Malabar Coast. A high pressure belt located in Deccan plateau checks the advance of the monsoon in northern regions. Assam and Bengal receive some rainfall through evening thunderstorms called knl baisakhi. Loa is the dry local wind that occurs in,the north-western region.

THE SOUTH-WEST MONSOON SEASON Due to the intense low pressure belt developed in the north-western plains, the south-west monsoon enters the Indian sub­continent. It blows from the Bay of Bengal and the Arabian Sea.

The normal dates of the onset of monsoon are-May 20 in Andaman and Nicobar Islands, May 29 in Kerala, June 15 at Kolkata and July 1 at Delhi. Cherrapunji (1,070 em)
in Khasi hills receives the maximum amount of rainfall in the world due to local relief factors. Due to the Himalayan and Purvanchal Hills, the rain-laden winds move in north­west direction and cause rainfall in the plains (due to easterly current).
Easterly Depression means a series of depressions which originate in Bay of Bengal. It travels in north-westerly direction and causes rainfall.