The hot season from March to May is  the  traditional period when the winter pattern  of pressure  and winds gets  disturbed prior to the establishment of the summer monsoon  and hence, is often referred to as 'Pre - Monsoon' season.  This season is characterised by heavy dust haze and extremely high temperature over  North India.  Land and sea breeze effect is prominant over the coastal areas during this season.  The frequency of thunderstromes increases progressively over south India with increased influx  of moist air from the sea.  As the season advances, a few tropical cyclones form in the Indian seas,  but they generally move north or northeast and strike the Bengal, Bengladesh or Burma coasts.

                                 Convective activity is essential for the occurence of thunder and dust stroms.  With the advance of summer, thunder activity becomes pronounced in April and May due to ground heating mainly over inland stations.
                                   In Tamil Nadu May is the hottest  Month with the mean daily maximum temperature os 36C in the plains, hilly region in the west recording about 13C lowest.  The highest temp  ever recorded at  an individual station in the plains is 46.3 at Thirupattur on 4th May 1976 which is 9.6C higher than the normal for the warmest month.  Uthagamandalam a hill station registered the highest maximum temperature of 28.5C on 29th april 1986 which was 5.8C higher than the normal  for the warmest month.