Planning for the weather is a good way to make your trip to Phuket relaxing and enjoyable, especially when you’re splurging. The hottest months are usually March and April with an average temp of 83°F, while the coldest months are January and February with an average of 81°F. The rainiest months in Phuket are September, October, July, and August, with each month seeing an average of 14 inches of rainfall.