The climate of Rajasthan can be divided into four
seasons: Summers, Monsoon, Post-Monsoon and winter.

The
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).
The Monsoon
The second season Monsoon extends from July 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
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.
The
Winter
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.