Planning for the weather is an important factor for making your trip to Tha Sao a success, especially when you’re splurging. The hottest months are usually April and March with an average temp of 86°F, while the coldest months are December and January with an average of 79°F. The rainiest months in Tha Sao are September, October, August, and July, with each month seeing an average of 8 inches of rainfall.