If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Phimai: The hottest months are usually April and March, with an average temperature of 29°C, while the coldest months are December and January, with an average of 25°C. The rainiest months in Phimai are September, August, October and July, with each month seeing an average of 234 mm of rainfall.