According to http://weatherspark.com/averages/33979/Hat-Yai-Songkhla-Thailand
The warm season lasts from March 4 to May 15 with an average daily high temperature above 33°C. The hottest day of the year is April 13, with an average high of 34°C and low of 24°C" .
But I claim an attack of confusion since February is the driest month with the chance of rainfall only 20% on any given day.
Not much of a defence, I know, but the best I can come up with!