May · Thailand weather
Thailand in May: Weather, What to Expect & Where to Go
May is the official start of the rainy season. Storms are heavy but usually short and predictable — an afternoon downpour, then sunshine. The Andaman coast gets the worst of it; the Gulf side stays mostly dry. Prices drop sharply.
Best region
Gulf
Samui and Phangan are still mostly dry, and noticeably less crowded than the winter peak.
Avoid
Andaman
The southwest monsoon hits the Andaman coast first — rough seas, heavy rain, dive boats stop running.
Good for
Gulf islands, fewer crowds, lower prices
May weather, region by region
Average temperatures and rainfall across Thailand's five climate regions in May. Tap the climate map on the homepage for an interactive month-by-month view.
| Region | Avg temp | Rainfall | Visit rating |
|---|---|---|---|
North Chiang Mai | 29°C | 170mm | Great |
Northeast Nakhon Ratchasima (Korat) | 30°C | 180mm | Good |
Central Bangkok | 30°C | 220mm | Good |
Andaman Phuket | 29°C | 280mm | Good |
Gulf Koh Samui | 30°C | 160mm | Great |
City spotlights
One city per region — what May actually feels like on the ground, and what to do or skip.
North
Chiang Mai
The first storms wash the haze away — the mountains are green again. Cheaper rates, fewer tourists, and beautiful late-afternoon light after the rain.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Northeast
Nakhon Ratchasima (Korat)
First storms break the heat and green up the Korat plateau. Khao Yai's waterfalls start to swell — Haew Narok is impressive after a week of rain.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Central
Bangkok
Hot, sticky, and prone to dramatic afternoon storms. Mornings are workable; evenings can flood with little warning.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Andaman
Phuket
Monsoon arrives in earnest. Hotels are cheap, mornings can still be glorious, but you'll lose dive days and risk a washout.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Gulf
Koh Samui
Hands-down the best beach option this month. Dry side of the country, reliable sun, and shoulder-season pricing.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Events & festivals in May
Royal Ploughing Ceremony
An ancient ceremony at Sanam Luang in Bangkok marking the start of the rice-planting season. A national holiday with a public day off.
Is May a good time to visit Thailand?
May is a budget-friendly shoulder month. If you stick to the Gulf islands or accept the rain elsewhere, it's a great month for value — just don't plan a diving-focused Andaman trip.
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Thailand in April
Songkran nationwide, Gulf islands at their best
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Thailand in June
Gulf islands, Chiang Mai's green season, value travel
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