Covering a total area of 217 square kilometres, Koh Chang lies off the east of the Trat province. It’s 30 kilometres long and almost 14 kilometres wide. Located in the eastern part of Thailand with Cambodia as its neighbor, Trat is a fertile province that produces rubber and a myriad tropical fruits.
The majority of the island is dominated by jungle-clad mountains, making it one of the islands with the highest amount of precipitation per year. Its national marine park covers 650 square kilometres (70% of it is offshore). Measuring 743 metres above sea level, Khao Salak Phet is the highest elevation. Koh Chang boasts over a dozen beaches and the most popular among tourists include White Sand Beach, Klong Prao Beach, Kai Bae Beach and Lonely Beach.
Its steep jungle-clad mountains (terrain ideal for localized precipitation) help make Koh Chang one of the wettest islands in the country. Its weather can be quite unpredictable. However, even during the wettest of its three seasons, you can expect it to be warm and humid with periods of prolonged sunshine (no guarantees though!).
The rainy season runs from June through till October, the cool(er) season from November to February, and the hot season from March till May. If good weather is a must, the best time to go is between November and February as it’s not too humid and the skies very clear. On the flipside, the beaches are at their busiest and the hotels hike up their rates.
The good thing about rain here is that it rarely lasts all day long. Normally a brief downpour will be followed by bright sunshine and a clear blue sky. So even if you're traveling during the monsoon season, you'll still get a fair amount of sunshine and a desirable tan. Please note that gaining access to some of the islands south of Koh Chang might not be possible during the rainy season, so check beforehand.