Thailand’s weather isn’t one climate on one calendar, it’s several regional patterns running at once, and most quick answers flatten that into “November to February is best” and stop. This page is the reference underneath that answer: actual temperature ranges and rainfall patterns, month by month, for the four regions that matter to travelers, Bangkok/central Thailand, the north, the Andaman coast and the Gulf coast. If you want a direct recommendation on when to book, see outthailand.com’s best time to visit Thailand guide; if you want the deep dive on what the wet season actually feels like day to day, see the Thailand rainy season guide. This one just answers “what’s the weather like in [month],” region by region.
Figures below are long-term seasonal averages compiled from climate-data sources and outthailand.com’s own regional guides, listed in Sources; any single year can run warmer, cooler, wetter or drier than the pattern. Prices are in Thai baht (THB) with US dollars in parentheses at ฿33 = US$1 (July 2026).
Table of Contents
- Thailand weather by month: the full table
- What are Thailand’s three broad seasons?
- What’s the weather like in Bangkok and central Thailand?
- What’s the weather like in the north (Chiang Mai, Chiang Rai)?
- What’s the weather like on the Andaman coast (Phuket, Krabi)?
- What’s the weather like on the Gulf coast (Koh Samui, Koh Phangan, Koh Tao)?
- FAQ
Thailand weather by month: the full table
Read this table region by region for whichever leg of your trip you’re planning, since no single month suits all four columns at once.
| Month | Bangkok / Central | North (Chiang Mai) | Andaman (Phuket, Krabi) | Gulf (Koh Samui, Phangan, Tao) | Verdict |
|---|---|---|---|---|---|
| January | Cool, dry; 22-32°C | Cool, dry; can dip to teens at night | Driest month; 31-33°C | Wet season easing; 31-32°C | Best broadly, book early |
| February | Warming, still dry; 24-33°C | Dry; smoke season starting late month | Driest window continues; 32-33°C | Driest month of the year here | Gulf coast’s sweet spot |
| March | Hot, dry; up to 35°C+ | Hot and dry; smoke season typically worst | Dry, warming; 32-34°C | Dry, warm; 31-33°C | Avoid the north; beaches fine |
| April | Hottest month; often 36-40°C | Very hot; smoke easing late month; Songkran Apr 13-15 | Hot but drier air; 32-34°C | Hot, dry; 31-33°C | Hottest everywhere; Songkran |
| May | Rainy season begins; 30-35°C | Rain increasing; 28-33°C | Monsoon starts fast, rain builds | Still mostly dry, sheltered | Andaman/mainland turning wet |
| June | Frequent short downpours; 27-34°C | Lush, green; 26-32°C | Rougher seas, regular rain | One of the Gulf’s better months | Gulf coast a good pick |
| July | Rainy, short storms; 26-33°C | Wetter but workable; 26-31°C | Steady monsoon rain continues | Secondary dry window opens | Gulf coast still strong |
| August | Among the wettest months; 26-33°C | North’s wettest month | Rain persistent, west-coast red flags | Still in the dry window | Gulf coast, indoor backups elsewhere |
| September | Bangkok’s wettest month; 25-32°C | Wet but easing; 25-30°C | Very wet, nearing peak | Dry window closing | Flexible itineraries only |
| October | Flood risk continues, easing late month | Rain easing toward dry season | Wettest tail, 315-325mm in Phuket | Own wet season starting | Transitional everywhere |
| November | Cool season begins; 24-31°C | Dry season begins, clear skies | Seas calming, dry season nearing | Wettest month by far, ~445mm | Good except Gulf coast |
| December | Cool, dry, most comfortable; 21-31°C | Cool, dry; can be chilly at night | Driest stretch, 80mm or less | Still recovering from wet spell | Bangkok, Andaman, the north |
Temperature ranges and rainfall figures are long-term averages compiled from Climates to Travel and outthailand.com’s regional best-time guides; individual years vary. Full detail on booking decisions is in the best time to visit Thailand and Thailand rainy season guides.
What are Thailand’s three broad seasons?
Nationwide, Thailand runs on three broad seasons tied to the Asian monsoon system. Cool season (November-February) is the most comfortable stretch almost everywhere, daytime highs typically 20-32°C, lower humidity, and noticeably cooler evenings in Bangkok and especially the north. Hot season (March-May) turns dry air into genuinely hot air, with April usually the peak, commonly 35-40°C in Bangkok and the north and a touch cooler on the coasts thanks to sea breezes. Rainy season (June-October) brings the year’s heaviest rain to the mainland, the north and the Andaman coast, usually as a short, intense afternoon or evening downpour rather than constant drizzle. That’s the pattern most generic weather summaries stop at, and it’s accurate for most of the country, but it misses the Gulf coast entirely, which runs on its own separate clock (see below).
What’s the weather like in Bangkok and central Thailand?
Bangkok’s temperature barely dips below 21°C even in the coolest nights of December and January, and climbs past 36°C at the April peak, so “cool season” here means comfortable rather than actually cold. Rain builds from May, and September is typically Bangkok’s wettest month, averaging around 335mm over roughly 21 rainy days, with recurring, real (if usually short-lived) street flooding in low-lying sois and underpasses. By November the rain has mostly cleared and the cool season sets in through February. If you’re weighing whether that flood risk should change your dates, outthailand.com’s Thailand rainy season guide covers it in more depth.
What’s the weather like in the north (Chiang Mai, Chiang Rai)?
The north shares Bangkok’s three-season shape but with a wider temperature swing and one extra variable. Cool-season nights in Chiang Mai and the surrounding hills can fall into the teens Celsius, genuinely chilly after dark, while daytime highs stay pleasant in the high 20s to low 30s. Hot season pushes daytime temperatures well past 35°C, and August is typically the north’s wettest month, at roughly 225mm, though the rain also clears the air and makes for some of the region’s most lush, photogenic scenery. The extra variable is smoke (burning) season, roughly February through April and typically worst in March, when agricultural fires across the region and over the border push air quality into unhealthy territory some days. That’s a genuine planning factor, not blogger exaggeration, and it’s covered in full, AQI figures included, in outthailand.com’s best time to visit Chiang Mai guide.
What’s the weather like on the Andaman coast (Phuket, Krabi)?
Temperatures on the Andaman coast stay comparatively flat year-round, typically 31-34°C, so rainfall, not heat, is what actually drives the “when to go” decision here. Facing the southwest monsoon, rain builds fast from May (roughly 295mm in Phuket) to a wet peak in September-October (around 315-325mm), then drops sharply by December (roughly 80mm) and stays low through February-March (around 35-40mm). That gives the Andaman coast its driest, calmest window from December through March, its best diving visibility and stillest seas, against a genuinely wet, choppier May-through-October stretch with reduced boat schedules on some routes. Full month-by-month detail, including seasonal closures, is in outthailand.com’s best time to visit Phuket guide.
What’s the weather like on the Gulf coast (Koh Samui, Koh Phangan, Koh Tao)?
This is the pattern most generic Thailand weather content gets wrong by omission. The Gulf islands sit on the peninsula’s east-facing side, largely sheltered from the southwest monsoon that soaks the mainland and the Andaman coast, which is why they can stay comparatively dry through July-August while Phuket is at its wettest. But they pay for that shelter with their own wet season instead: the northeast monsoon, roughly October through December, dumping rain onto these islands specifically. Koh Samui’s numbers show the swing clearly, averaging around 65mm in February versus roughly 445mm in November, by far the wettest month of any region in this guide. Temperatures stay warm and fairly steady year-round, typically 31-33°C, so, like the Andaman coast, rainfall is the variable that actually matters here. For the fuller regional breakdown, see outthailand.com’s best time to visit Koh Samui guide.
The honest caveat: these are patterns, not forecasts
Every figure above is a long-term seasonal average, useful for planning a trip months out, but not a substitute for checking an actual forecast once your dates are close. A given April can run hotter or milder than the long-term number; a given November can dump more or less rain on the Gulf islands than the 445mm average suggests. Treat this page as the shape of the year, then check a real forecast (or outthailand.com’s live Thailand events listings for what’s actually scheduled) as your trip approaches.
Where to next
For a direct recommendation on when to book rather than just the raw weather patterns, see outthailand.com’s best time to visit Thailand guide. Going deep on the wet season specifically, including what closes and what the rain actually feels like, the Thailand rainy season guide covers it region by region. Heading to a specific base, see best time to visit Chiang Mai or best time to visit Phuket for that location’s full detail. And to see what’s actually on while you’re deciding your dates, browse the latest Thailand events.
Sources
- Climates to Travel: Bangkok Climate: month-by-month temperature and rainfall averages.
- Climates to Travel: Phuket Climate: Andaman coast temperature and rainfall averages, dry-season timing.
- Climates to Travel: Ko Samui Climate: Gulf coast temperature and rainfall averages, northeast monsoon timing.
- Climates to Travel: Chiang Mai Climate: northern Thailand temperature and rainfall averages.
- IQAir Newsroom: Chiang Mai ranks among the top 10 most polluted cities during Thailand’s burning season: March 2026 AQI readings, burning-season severity.
- outthailand.com Best Time to Visit Thailand: consolidated national and regional figures.
- outthailand.com Thailand Rainy Season: rain-pattern and closure detail by region.
- outthailand.com Best Time to Visit Chiang Mai: northern AQI figures and seasonal detail.
- outthailand.com Best Time to Visit Phuket: Andaman coast monsoon detail.
- outthailand.com Best Time to Visit Koh Samui: Gulf coast monsoon detail.
- Xe.com: USD/THB Currency Converter: exchange rate reference, July 2026.