The best time to visit Thailand
There is no single best month, because Thailand has two monsoon systems running in opposite directions. The right question is which coast you are going to.
Two coasts, opposite weather
The Andaman side — Phuket, Krabi, Phi Phi, the Similans — is at its best November to April, dry and calm, with the clearest water of the year. From May to October the southwest monsoon brings swell and rain, and several islands close outright.
The Gulf side — Koh Samui, Koh Phangan, Koh Tao — runs on a different schedule. Its best window is January to August, and its wettest months are October and November, when the Andaman is drying out. This is why the "best time to visit Thailand" question has two answers.
Bangkok and the north
Bangkok is a year-round city; the difference is comfort rather than possibility. November to February is cool and dry, 25–32°C, and genuinely pleasant. March to May is hot — 35–38°C in April — and Songkran in mid-April briefly shuts the city down in the best way.
The north has a third season nobody mentions: February to April is burning season, when agricultural fires and haze drop visibility and air quality across Chiang Mai and Chiang Rai. It is not a reason to avoid the north entirely, but it is a reason not to plan a mountain-photography trip in March.
The green season argument
June to October gets called the rainy season, which is misleading. Rain comes in intense afternoon bursts that last an hour, not all-day drizzle. Hotels are 30–50% cheaper, the landscape is green, and the temples are empty. If you are travelling for culture rather than beaches, it is arguably the better time to come.
What we would book, by month
Jan–Feb — anywhere. The best two months in the country.
Mar–Apr — Andaman coast, and Songkran if you want it.
May — Gulf coast, or the north before the haze builds.
Jun–Sep — Gulf coast and the north; Andaman only if you accept cancelled boat days.
Oct — the awkward month: Andaman is still wet, Gulf is getting wet. Bangkok and the north.
Nov–Dec — Andaman, and the north for Yi Peng.
What is the cheapest month?
September and October, when both coasts are unsettled. Hotel rates drop 40% and the temples are empty.
Is the rainy season really that wet?
No. Expect one heavy hour most afternoons, not constant rain. The exception is October on the Gulf coast, which can rain for days.
When should I avoid Thailand?
Songkran week if you do not want to be soaked, and the north in March if air quality matters to you.
Tell us the trip you have in mind.
Dates, people and the one thing that must happen — we come back with a route and a real cost.
Written and checked by the Travel Thailand Tour team, Bangkok · Last updated · Prices are per person and were correct at the time of writing.