Planning for the weather is a good way to make your trip to Chanthaburi relaxing and enjoyable, especially when you’re splurging. The hottest months are usually April and March, with an average temperature of 28°C, while the coldest months are January and December, with an average of 26°C. The rainiest months in Chanthaburi are September, July, August and June, with each month seeing an average of 423 mm of rainfall.