Planning for the weather is an important factor for making your trip to Mae Sai a success, especially when you’re splurging. 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.