The weather in Thailand is classified as hot and humid, with a long monsoon season.
Thailand has three official seasons - hot, cool, and wet.
The hot season runs from March through to June, with April and May the hottest months of the year.
The monsoon season usually is accompanied by heavy rain but will normally have rough seas.
This season can vary from year to year.
On the Andaman Sea / Phuket / Krabi / Khao Lak or west side of the Isthmus this can start as early as April or May, although it officially begins in June and runs as late as October, when the temperatures begin to cool slightly. In the south, (including the Andaman islands), the rains don't end until late November.
On the Gulf Coast / Samui / Phangan / Tao this can start as early as October, although it officially begins in November and runs as late as May.
The rain isn't constant in the early months of the period as it will rain for one or two hours, and then dry out. However, it can rain torrents when it does rain. Be aware that late in a monsoon season is when the rains are at their heaviest and most persistant, and flash flooding can occur. Carry an umbrella or raincoat, or head inside for shopping or a massgae, you can still enjoy a great holiday in the Thai rainy season.
The cool season normally runs from November thru February and will still feel hot to most visitors, but much of the country does experience a short cold snap for a week or so in December, especially in the north and notheast where it can get quite chilly.
Whenever you’re visiting be sure to bring plenty of breathable and light clothes, and a lot of good sunscreen. The sun can be quite intense. But at least there is typically a lot of it to enjoy!
Best time to visit?
Andaman Sea / Phuket / Krabi / Khao Lak - November to May
Gulf Coast / Samui / Phangan /Kho Tao - April to October
Out of these times there may be some bargains to be had if you are prepared to put up with the risk of rain!
Real-Time Weather Reports
You can use this link to check on the current weather conditions anywhere in Thailand.. Updated in real time. You can select regions and then cities from the left navigation. http://www.tmd.go.th/EN/ - for Phuket click here: Phuket Weather