Andaman is an island and therefore, experiences a moderate temperature all around the year (within the range of 23 to 31 degree Celsius). However, the climate is tropical with warm summers (March to May), cool & pleasant winters (December to February) and heavy rains during the monsoon season (May to August). The best time to enjoy all sorts of underwater activities and other sightseeing, the best time is from the month of October to May. So, keep this information in mind while planning your Andaman trip.