Weather will likely play an important role when you plan your trip to Surat Thani, and keep 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 temp of 82°F, while the coldest months are January and February with an average of 79°F. The rainiest months in Surat Thani are November, October, May, and September, with each month seeing an average of 11 inches of rainfall.