Planning for the weather is an important factor for making your trip to Chonburi a success, especially when you’re splurging. The hottest months are usually April and May with an average temp of 85°F, while the coldest months are December and January with an average of 81°F. The rainiest months in Chonburi are September, October, July, and August, with each month seeing an average of 8 inches of rainfall.