Taking into account the local weather in Tha Mo Sai is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually March and April with an average temp of 81°F, while the coldest months are February and January with an average of 78°F. The rainiest months in Tha Mo Sai are November, December, October, and May, with each month seeing an average of 12 inches of rainfall.