India's climate is strongly influenced by the Himalayas and the Thar Desert, both of which drive the monsoons. The Himalayas prevent cold Central Asian Katabatic wind from blowing in, keeping the bulk of the Indian subcontinent warmer than most locations at similar latitudes. The Thar Desert plays a crucial role in attracting the moisture-laden southwest summer monsoon winds that, between June and October, provide the majority of India's rainfall. Four major climatic groupings predominate in India: tropical wet, tropical dry, subtropical humid, and montane.
The weather is hot most of the year with variations from region to region. The coolest weather lasts from around December to February, with fresh mornings and evenings and mostly sunny days. The really hot weather, when it is dry, dusty and unpleasant, is between March and June. Monsoon rains occur in most regions in summer anywhere between June and early October.
Season of India : Though divided into different climatic zones, India seems to be unified by primarily four seasons- Winter, Summer, Advancing Monsoon and Retreating Monsoon.
Winter: December to February is the wintertime in almost all of India. At this time of the year, days are cold with average temperature of10-15 ?C, but it can drop down to below 0 ?C in some higher ranges of northern India. Normally winters are dry in northern India. In Southern part, the temperature difference is not so marked due to moderating effect of Indian Ocean, Bay of Bengal and Arabian Sea.
Summer: March, April, May and June are the summer months in India. It is a time period when rays of the sun fall vertically on Indian subcontinent. The average temperature is around 32 c but in western region the maximum temperature can be far above the average. Hot wind, known, as 'Loo' is the marked feature of summers in northern India.
Advancing Monsoon: It is the time period when India gets major part of its share of rain. Months of June, July, August and September form the core of Advancing Monsoon in almost all parts of country. The monsoon approaches with moisture laden winds, this sudden approach is marked with violent thunderstorms and lightening, known as 'break' of the monsoon.
Retreating Monsoon: This season starts, when monsoon after drenching all of India, begins to retreat. With the month of September, rainfall began to decrease and as we approach November, the monsoon is completely gone from major part of India, except for Tamil Nadu and some other southern states, which also receive rain from Western Disturbance.