The best time to travel in Thailand in terms of climate is from October to May. During these months it rains the least and is not as hot, however the peak tourist months (November to April) also lie in this period. It is probably best to avoid the months between May to June as the weather becomes unbearably hot, while the following months bear the brunt of the monsoon. Expect to get wet if you come during the monsoon (June-October).

In autumn (May to October), it is not possible to visit some of the islands south of Koh Chang because of the monsoon. These islands include Koh Kut, Koh Mak, Koh Wai, and Koh Khlam. The islands that are not too distant from Koh Chang can be visited all year round.

The traditional Thai New Year is joyfully celebrated throughout the country on the 13th to 15th of April in the Songkran Festival. Rituals of merit making, cleaning houses, honouring elders, parades of dancers and music troupes, and boat races make the festival a vibrant affair. Perhaps the best parts are the water fights, a great way to cool off in the hot season. Because of the water fights, it is also known as the "Water Festival" as people believe that water will wash away bad luck.