Cold Weather Season
This season usually begins with late-November in northern India. The duration of cold weather season is from December to February. January is the coldest month over most parts of the country as sun shines vertically over the Tropic of Capricorn in the southern hemisphere.
Northeast Monsoon Winds
The temperature increases as one moves from north to south. As a result of low temperatures, a feeble high pressur.e area develops over northern parts of India. This mild high pressure causes the off-shore Northeast monsoon winds. These land bearing winds being cold and dry don’t give rain over most parts of the country. However, these winds cause rain along the Coromandel coast since they collect moisture on their way over the Bay of Bengal.
Western Disturbances
The succession of depressions is another feature of this season. These low pressure systems are called Western disturbances as they originate in the mediterranean region. These depressions move with the westerly jet streams. Covering a long distance over Iraq, Iran and Pakistan, they reach India around mid December. Their arrival results in the increase of temperature and in light rains over northern plains. They cause wide spread snowfall over western Himalayas and the adjoining ranges.
The meager rainfall caused by these disturbances is of great importance to the standing crops, particularly the wheat, in unirrigated areas. These depressions are followed by cold waves which bringdown temperatures considerably.
Important Characteristics
- Low temperatures in the north and their gradual increase towards southern parts of India.
- Blowing of cold and dry northeast monsoon resulting in dry weather conditions in most parts. Coromandel coast receives rainfall during winter.
- Western disturbances cause light rain in northern plains and snowfall over the Himalayan ranges.