The climate of Rajasthan can be divided into four seasons: Summers, Monsoon, Post-Monsoon and winter.
Summer (April to June) : Summer A summer, which extends from April to June, is the hottest season, with temperatures ranging from 32 degree C to 45 degree C. In western Rajasthan the temp may rise to 48 degree C, particularly in May and June. At this time, Rajasthan's only hill station, Mt Abu registers the lowest temperatures. In the desert regions, the temperature drops at night. Prevailing winds are from the west and sometimes carry dust storms (we call them aandhi).
Monsoon (Late June to September) : The second season Monsoon extends from Late June to September, temp drops, but humidity increases, even when there is slight drop in the temp (35 degree C to 40 degree C). 90% of rains occur during this period.
Post Monsoon (October to November) : The Post-monsoon period is from October to November. The average maximum temperature is 33 degree C to 38 degree C, and the minimum is between 18 degree C and 20 degree C.
Winter (December to March) : The fourth season is Winter or the cold season, from December to March. There is a marked variation in maximum and minimum temperatures, and regional variations across the state. January is the coolest month of the year. And temp may drop to 0 degree C in some cities of Rajasthan, like Churu. There is slight precipitation in the north and northeastern region of the state, and light winds, predominantly from the north and northeast. At this time, relative humidity ranges from 50% to 60% in the morning, and 25% to 35% in the afternoon