Taking into account the local weather in Ko Phra Thong can help you maximize your time at the pool during your trip. The hottest months are usually March and April with an average temp of 81°F, while the coldest months are January and February with an average of 79°F. The rainiest months in Ko Phra Thong are September, October, July, and August, with each month seeing an average of 15 inches of rainfall.