Planning for the weather is a good way to make your trip to Ko Chang Tai relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and March with an average temp of 81°F, while the coldest months are January and February with an average of 78°F. The rainiest months in Ko Chang Tai are September, July, August, and June, with each month seeing an average of 20 inches of rainfall.