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 Sukhothai: The hottest months are usually April and March, with an average temperature of 30°C, while the coldest months are December and January, with an average of 26°C. The rainiest months in Sukhothai are August, September, July and May, with each month seeing an average of 248 mm of rainfall.