Ko Chang's best weather by a wide margin: dry, sunny days, calm seas, and the lowest rainfall of the year. It's also the busiest and priciest stretch, the west-coast beaches and dive boats fill up and resort rates climb to their highest point of the year, so book ahead if you want a spot on White Sand or Klong Prao beach. December in particular is the coolest, driest month of the whole year.

This tier covers two different halves of the year. March and April are still technically dry season, hot and increasingly still, with only the first pre-monsoon showers appearing, while November sees the rains fade out fast as the dry season returns. July and October sit within the wetter half of the year, rain remains frequent, but conditions ease slightly compared to the deepest stretch of the monsoon on either side of them. Across all of these months hotel prices sit well below peak-season rates and the island feels noticeably quieter.

The core of Ko Chang's monsoon, when rain falls on most days and many of the smaller beachfront resorts and bars close for the season entirely. The heaviest downpours tend to arrive overnight or in the early morning, so afternoons are often more manageable than the totals suggest, but ferries can be cancelled in rough seas and outdoor plans need to stay flexible. It's also when you'll find the steepest discounts and the emptiest beaches of the year, if you don't mind the gamble.