If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Tha Sao: 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 Tha Sao are September, October, August and July, with each month seeing an average of 193 mm of rainfall.