The lower east (Coromandel) and west (Malabar) coasts of the Peninsula and the Ganges Delta are humid tropical; most of the Peninsula and the Ganges-Brahmaputra Lowland are moist subtropical to temperate; and the semiarid steppe and dry desert of the far west are subtropical to temperate. The northern mountains display a zonal stratification from moist subtropical to dry arctic, depending on altitude.
Extremes of weather are even more pronounced than the wide variety of climatic types would indicate. Thus, villages in western Rajasthan, in the Thar (Great Indian) Desert, may experience less than 13 cm (5 in) of rainfall yearly, while 2,400 km (1,500 mi) eastward, in the Khasi Hills of Assam, Cherrapunji averages about 1,143 cm (450 in) yearly. Sections of the Malabar Coast and hill stations in the Himalayas regularly receive 250–760 cm (100–300 in) yearly; many areas of the heavily populated Ganges-Brahmaputra Lowland and the Peninsula receive under 100 cm (40 in). Winter snowfall is normal for the northern mountains and Kashmir Valley, but for most of India, scorching spring dust storms and severe hailstorms are more common. The northern half of the country is subject to frost from November through February, but by May a temperature as high as 49° C (120° F ) in the shade may be recorded. High relative humidity is general from April through September. Extratropical cyclones (similar to hurricanes) often strike the coastal areas between April and June and between September and December.
The monsoon is the predominant feature of India's climate and helps to divide the year into four seasons: rainy, the southwest monsoon, June–September; moist, the retreating monsoon, October–November; dry cool, the northeast monsoon, December–March; hot, April–May. The southwest monsoon brings from the Indian Ocean the moisture on which Indian agriculture relies. Unfortunately, neither the exact times of its annual arrival and departure nor its duration and intensity can be predicted, and variations are great. In 1987, the failure of the southwest monsoon resulted in one of India's worst droughts of the century.