Weather will likely play an important role when you plan your trip to Mae Sai, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and March, with an average temperature of 27°C, while the coldest months are January and December, with an average of 20°C. The rainiest months in Mae Sai are August, July, September and June, with each month seeing an average of 318 mm of rainfall.