When to visit Thailand: the seasons, region by region
Three seasons, two coasts, and the months each one rains.
By the Local SIM Thailand team, checked October 2, 2026
The short answer
Thailand's cool season runs from November to February, coolest in December and January; the hot season runs from March to May, hottest in March and April; and the rainy season generally runs from May to October. The coasts rain on different clocks: around Koh Samui, the wet months usually come from November to March.
- Cool season: November to February, with December and January the coolest months.
- Hot season: March to May, hottest in March and April.
- Rainy season: generally May to October, with the Gulf coast's rain usually from November to March.
- Storms and flooding: typhoons can occur from April to November, and heavy rain can close roads, especially in the north.
- Air: seasonal smog affects Bangkok and the north in the dry season, including Chiang Mai.
Checked October 2, 2026
The regions, month by month
Bangkok and the centre
- The seasons
- Hot from March to May; December and January are the coolest months
- Rain
- May to October
The north (Chiang Mai)
- The seasons
- Cooler nights in the cool season, November to February
- Rain
- May to October; heavy rain can close mountain roads
The Andaman coast (Phuket)
- The seasons
- Warm through the cool season
- Rain
- The west coast's rain falls May to October
The Gulf islands (Koh Samui)
- The seasons
- Warm through the cool season
- Rain
- Usually November to March
Region by region
Bangkok
The city's coolest months are December and January, and October brings 24 to 32 degrees with lower humidity and light rain. March to May is the hottest stretch.
The north
Chiang Mai cools down from November to February, and the wet months from May to October can close mountain roads and trails.
The Andaman coast
Phuket's rain falls inside the May to October window, and the sea stays warm through the cool season.
The Gulf islands
Koh Samui and the south-east usually see their wet months later, from November to March.
The bottom line
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The rains do not arrive everywhere at once: check your stops' wet months, then plan the route around them.
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What is the best time to visit Thailand?
For most routes the cool, dry months from November to February are the most comfortable, and December and January are the coolest. March to May is the hottest stretch, and the Gulf coast's rain usually comes later, from November to March, so one window does not suit every route.
What is the Thailand weather like in the rainy season?
The rainy season generally runs from May to October, though the south-east and the Gulf islands around Koh Samui usually see it from November to March. Heavy rain can flood roads, and storms are possible from April to November.
When is it hottest in Thailand?
March to May, with temperatures highest in March and April; the coolest months are December and January.
Sources
Where the facts on this page come from.
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