High season in Phuket is from October to April. Top season, when reserving well in advance is always necessary, is from December the 15th to January the 15th. The rest of the year is low season.
Temperatures are moderately high all year round, day and night. An air conditioned room is recommended, but it is not imperative.
During the low season, the monsoon strikes. Heavy showers and strong winds keep European tourism away from Phuket. It is during the low season when tourists from the Persian Gulf come.