Knowing the Thailand weather month by month is the first step to planning a trip with no surprises. Thailand does not have one single climate: the north and the south behave differently, the east and west coasts run on opposite seasons, and picking the wrong month can turn a dream vacation into a week of rain.
Table of contents❯
Why the Weather Is the First Thing to Plan
Thailand does not have one single climate. The north and the south behave differently, the east and west coasts run on opposite seasons, and picking the wrong month can turn a dream vacation into a week of rain. This guide to Thailand weather month by month is the starting point for planning a trip that holds together.
November to February. Clear skies, comfortable temperatures, calm sea on both coasts.
they reach the west coast (Phuket, Krabi) from May to October, and the east coast (Koh Samui) from October to December.
heavy rain almost everywhere, plus a real cyclone risk in the Gulf of Thailand.
The Three Seasons of Thailand: How the Weather Changes Month by Month
Dry Season (November – February)
The season most travelers aim for. Temperatures between 20 °C (68 °F) and 33 °C (91 °F), very little rain, calm sea. It is the ideal time for the Andaman beaches (Phuket, Krabi, Koh Phi Phi) and for exploring Bangkok and Chiang Mai before the spring heat sets in.
What our team on the ground sees: A shifting climate has turned November and early December into a transition period. In those weeks an unsettled forecast or a choppy sea can call for a little flexibility, so boat trips are occasionally rescheduled and long transfers by bus, train or ferry sometimes run late. There is nothing to worry about — it is entirely normal at this point in the year — but if you want the steadiest weather and the smoothest logistics, January is still the best month of them all.
Hot Season (March – April)
Temperatures climb to 36 °C (97 °F), with April the peak. This is when Songkran, the Thai New Year, turns Bangkok into a city-wide water fight (April 13–15) — one of the most striking things you can witness in the country. Northern Thailand (Chiang Mai, Pai, Mae Hong Son) is best left out: these are the weeks of the burning season, when crop fires push air quality down. It is a northern problem only — the south and the islands are not affected.
Rainy Season (May – October)
The most misunderstood season. It does not rain all day: the usual pattern is a heavy downpour in the afternoon, followed by sun. The trick is knowing which coast to pick, because while the southwest monsoon blows, the east coast of the Gulf (Koh Samui, Koh Samet) stays largely sunny.
Thailand Weather at a Glance: Seasonal Averages, Month by Month
To help you plan, we have gathered the climate figures from the seasonal averages published by the Thai Meteorological Department.
The interactive table below gives you, for every month of the year, the average highs and lows, rainfall in millimeters, the number of rainy days and the humidity level, each with a short verdict you can read at a glance.
Move through the tabs, and read the Where to Go panel carefully: that is where you will find what to book and what to leave out in each month, and it is the key to understanding how differently the east and west coasts behave. Explore the table and find the right month to travel.
Weather Guide
Thailand Weather Month by Month
Temperatures · Rainfall · Humidity · Where to Go
| Month | Season | Max °C (°F) | Min °C (°F) | Rain mm | Rainy days | Humidity % | Verdict |
|---|---|---|---|---|---|---|---|
| January | Dry | 32° (90°) | 20° (68°) | 10 | 2 | 60% | ⭐ Excellent |
| February | Dry | 33° (91°) | 22° (72°) | 20 | 3 | 62% | ⭐ Excellent |
| March | Hot | 35° (95°) | 24° (75°) | 35 | 5 | 65% | ✅ Good |
| April | Hot | 36° (97°) | 25° (77°) | 65 | 7 | 70% | ✅ Good |
| May | Rainy | 35° (95°) | 25° (77°) | 200 | 16 | 78% | ⚠️ Caution |
| June | Rainy | 34° (93°) | 25° (77°) | 155 | 14 | 80% | ⚠️ Caution |
| July | Rainy | 33° (91°) | 25° (77°) | 170 | 15 | 82% | ⚠️ Caution |
| August | Rainy | 33° (91°) | 25° (77°) | 185 | 17 | 83% | ⚠️ Caution |
| September | Rainy | 33° (91°) | 24° (75°) | 215 | 19 | 84% | ❌ Avoid |
| October | Rainy | 32° (90°) | 24° (75°) | 180 | 16 | 80% | ⚠️ Caution |
| November | Dry | 31° (88°) | 22° (72°) | 55 | 8 | 70% | ✅ Good |
| December | Dry | 30° (86°) | 20° (68°) | 15 | 3 | 62% | ⭐ Excellent |
Monthly rainfall
Rainfall in millimeters (bars) and rainy days (line)
⚠️ Based on long-term climate averages. The weather varies from year to year.
Average monthly temperatures
Highs and lows in degrees Celsius (Fahrenheit in the table above)
⚠️ Based on long-term climate averages. The weather varies from year to year.
Average relative humidity
Monthly average, in percent
⚠️ Based on long-term climate averages. The weather varies from year to year.
Where to Go, Month by Month
Pick the month of your trip to see where to go
⚠️ Based on long-term climate averages. Local conditions can vary.
What to Pack: Getting Your Bag Right for the Tropics
Packing for a tropical climate takes a couple of small tricks. Go for light clothing in natural fabrics such as cotton and linen, which keep breathing even on the muggiest afternoons. One extra tip: always keep a spare t-shirt in your daypack, especially if the humidity tends to leave you soaked.
Do not leave out a light rain jacket or a compact umbrella for the sudden tropical downpours (though both are easy to pick up in any local 7-Eleven). Just as important is a light sweater or a shawl: the air conditioning in malls and on public transport is often fierce, and the sudden change in temperature is a quick way to catch a chill.
Among the things you should not skip: a broad-spectrum sunscreen, sunglasses and a hat. If you plan to head inland or do any hiking, bring comfortable, breathable shoes; and for temple visits, choose footwear you can slip off and back on in seconds. With the right kit in your bag, you will enjoy every side of the trip, whatever the forecast says.
Practical Tips for Planning Around the Weather
December and January are the peak months, hotels and flights often sell out many months ahead.
From May to October rates fall by 30–50% and the crowds thin out. Pick the right destination (the east coast, or Bangkok) and the trip is every bit as good.
Do not go by the month alone; check the outlook in the 7–10 days before you fly. A tropical climate can surprise you in both directions.
It is the one month when we actively advise against the beach destinations on either coast, because of the sheer volume of rain.
A one-of-a-kind experience, but it comes with extreme heat and blocked streets: it is not the right window for every traveler.
Back to the Main Guide
Clearer about when to visit Thailand? To put the rest of the trip together — transport, budget, suggested itineraries and much more — head back to our ➡️ Complete Thailand Travel Guide.
FAQ
Which is the best month to visit Thailand?
The best window runs from November to February, with January and February the two strongest months of all. Clear skies, temperatures between 20 °C (68 °F) and 33 °C (91 °F), a calm sea on both coasts and very little rain anywhere in the country.
If you are free to choose, January offers the best conditions for almost every destination: the dry season is at its height, the beaches of Phuket and Krabi are at their finest, and even the north, Chiang Mai, Pai, is comfortable, well before the spring heat. February is near enough identical, with the advantage of being a little less busy.
That said, December is excellent on the Andaman coast, while November strikes a good balance between weather and rates that have not yet reached the January peak. And if an afternoon shower does not put you off, May and June on the east coast of the Gulf, Koh Samui, Koh Samet, are a surprisingly strong alternative, with fewer people and lower costs.
Can you travel to Thailand during the monsoon?
Yes, absolutely. While the southwest monsoon runs (May to October) the east coast of the Gulf, Koh Samui, Koh Samet, Koh Tao, stays mostly sunny. Bangkok and Chiang Mai work all year round. The one month to rule out without hesitation is September.
The big misunderstanding about the monsoon is the idea that the whole country shuts down from May to October. In reality Thailand has two coasts with opposite rainfall patterns, and that changes everything. While Phuket, Krabi and Koh Phi Phi take heavy rain, Koh Samui and Koh Samet sit in the lee of the southwest wind and enjoy far better conditions.
Bangkok and Chiang Mai stay fully open too: the rain usually falls in the late afternoon and lasts a couple of hours, leaving the mornings free for sightseeing. The upside of the low season is real, rates down by as much as 40–50%, fewer people and a more ordinary, more genuine atmosphere. September is the only month we rule out flatly: rainfall peaks across almost the whole country and the cyclone risk in the Gulf is not theoretical.
When is the best time to visit Phuket?
Phuket is at its best from November to April, peaking between December and February. In those months the sea is calm, the sky is clear, and conditions for the beach and for snorkeling are excellent. From May the monsoon brings a rough sea and frequent rain.
March and April still work well, but the heat climbs noticeably, up to 36 °C (97 °F), and the sea becomes less predictable towards the end of April. From May onwards the southwest monsoon hits Phuket with growing force: waves can make swimming dangerous on some beaches, and the red flag goes up regularly. September and October are the toughest months.
One detail that often catches people out: if you travel in December and plan to pair Phuket with Koh Samui, be aware that the two run on opposite seasons. December is ideal for Phuket but awkward for Koh Samui, where the northeast monsoon brings rain and a rough sea. Better to fit Koh Samui into a different part of the trip.
When is the best time to visit Koh Samui?
Koh Samui is at its best from March to September, peaking between April and August. Unlike Phuket, it sits on the east coast and follows the opposite pattern: sunny while the southwest monsoon blows, wet in winter. November and December are the two months to avoid.
This feels counterintuitive if you associate the monsoon with the whole country, but Koh Samui is sheltered from the southwest wind and takes its main rain only from October to December, driven by the northeast monsoon. Statistically November is the wettest month on the island, with a risk of rough seas and flooding.
For that reason Koh Samui is not the obvious pick for Christmas and New Year, unless you are willing to accept gray days and a choppy sea. If your trip falls in summer, on the other hand, Koh Samui is one of the most reliable destinations in Thailand: sunny days, a calm sea and resorts that are far less crowded than the Andaman side gets in its own winter high season.
Does it get cold in Thailand in winter?
Not in the ordinary sense. In Bangkok and the south, winter lows sit around 20–22 °C (68–72 °F). In the north (Chiang Mai, Pai) nights between December and February can drop to 8–12 °C (46–54 °F), so a light fleece is worth packing.
In Bangkok and across southern Thailand the temperature stays pleasant even in the coolest months: between December and February highs hover around 30–32 °C (86–90 °F) during the day, with overnight lows near 20–22 °C (68–72 °F). It is a mild, easy climate, nowhere near anything you would call cold.
The north is a different story. In Chiang Mai, Pai and the mountain areas, night temperatures from December to February can fall below 10–12 °C (50–54 °F), and in some highland spots they come close to 8 °C (46 °F). Daytime readings climb back to 25–28 °C (77–82 °F) without trouble, but the swing is considerable. If you are planning a multi-day trek or nights in mountain lodgings, bring a light fleece or a windproof jacket. For the south and the islands, winter is simply the finest season, and nothing heavy is needed.
What should you pack for a trip to Thailand?
The essentials: light clothing in cotton or linen, SPF 50+ sunscreen, a compact rain jacket for the tropical downpours and a light sweater for the fierce air conditioning on transport and in malls. For temples, shoes you can slip off easily.
The golden rule is to favor breathable natural fabrics, which make all the difference on the muggiest days. An ultralight rain jacket or a compact umbrella is worth its space, though both are easy to find in any 7-Eleven for very little. Do not underestimate the sweater: the jump between the street and an air-conditioned room is one of the most common mistakes among people heading for the tropics convinced they will never need anything warm.
Among the must-haves, do not forget a broad-spectrum sunscreen, decent sunglasses and a hat. If you plan to hike inland, go for comfortable, breathable shoes. For temple visits, and there will be plenty, choose footwear you can take off and put back on quickly: going barefoot is required in almost every sacred site in Thailand. With the right bag, you will enjoy every side of the trip, whatever the weather has in store.