Where is it dry in Thailand in December?
The north and the centre. Bangkok, Chiang Mai and Hua Hin get 9 to 19 mm in the month, on 1 to 2 days of 31. That is why "December is the dry season" is mostly true. It is not true everywhere, because Thailand has three coasts and in December they are at three stages of the same change. The north and centre have been dry since November, the Andaman coast (Phuket, Krabi, Koh Lanta) is half way, and the Gulf islands (Koh Samui, Koh Phangan) are still in their wet season. Here are all eight places in one table:
December averages, side by side
| Place | High | Low | Rain | Rain days |
|---|---|---|---|---|
| Bangkok | 31° | 22° | 9 mm | 1 |
| Chiang Mai | 27° | 17° | 16 mm | 1 |
| Hua Hin | 29° | 23° | 19 mm | 2 |
| Phuket | 29° | 25° | 80 mm | 9 |
| Krabi | 30° | 23° | 98 mm | 10 |
| Ko Lanta | 29° | 25° | 88 mm | 8 |
| Koh Samui | 28° | 25° | 318 mm | 10 |
| Koh Phangan | 28° | 25° | 286 mm | 9 |
Averages 2015-2025 · Source: Open-Meteo, CHIRPS · How we measure
Read the rain columns together. A rainy day here is a day with at least four millimetres, so a short shower that leaves the day mostly sunny does not count, and the millimetres say how hard it fell. Bangkok, Chiang Mai and Hua Hin are the dry rows. Month by month: Bangkok, Chiang Mai, Hua Hin.
Where to be next: your month-by-month route, $19
A route for your months with a leave-by date for each stop, a backup, and the seasonal traps on your path. Drafted from 11 years of weather data, every number checked against it, in your inbox within 48 hours. Not included: visas, insurance or bookings.
Is Phuket good in December?
Better than November, not yet at its best. Phuket, Krabi and Koh Lanta fall from 200 to 235 mm in November to 80 to 98 mm in December, and to under 80 mm in January. There are still 8 to 10 rainy days, and about three quarters of the sky is cloud, so even a dry beach day is often a grey one. Late December is a better bet than early December, and January is better than either. That is the direction the monthly averages show; we hold no half-month figures, so we do not give a first-half and second-half split. Our Phuket in November guide shows the step down in detail.
If you are fixed on the Andaman coast, choose Phuket or Koh Lanta over Krabi on the numbers, and book the first week refundable.
Is Koh Samui rainy in December?
Yes, and it is the trap. Koh Samui and Koh Phangan have about as many rainy days as Phuket, but they collect close to four times the water on them. If a friend says "December is great in Samui", that can be true of a week. The eleven-year average says a month there is a wet one.
Koh Samui: Average high and low temperature, °C
Koh Samui: Rainfall, mm
Averages 2015-2025 · Source: Open-Meteo, CHIRPS · How we measure
The chart shows why. Samui's rain peaks in November at 457 mm, falls to 318 mm in December and to 152 mm in January, so it is the slowest of our eight places to dry out. The good months are February and March; see Koh Samui and Koh Phangan: best time. For all three coasts across the year, see Thailand rainy season by coast.
How warm is Thailand in December?
Warm everywhere, and cool at night in the north. Bangkok reaches 31°C by day, the Andaman coast 29° to 30° and the Gulf islands 28°. Chiang Mai is the coolest at 27° by day and 17° at night, so bring a layer for mornings, especially on a scooter. It is the comfortable range for working outdoors, not the heat of April.
What about air quality and haze?
Bangkok is the exception to "dry means clear". Its rain is only 9 mm, but its air is not clean. In our model data for 2023 to 2025 the December average sat above the WHO daily guideline in every year, with several bad days each month. The model reads low on bad days, so treat that as a floor, and see our Bangkok air quality guide for the whole year.
Chiang Mai's smoke season comes later in the dry season. It starts in January, and even its first weeks read above the guideline in our model data. If you plan to stay into the new year, see the Chiang Mai burning season guide.
Where should a remote worker base themselves in December?
On weather alone:
- Sun and certainty, beach optional: Bangkok or Chiang Mai. Pick Chiang Mai for cool mornings and Bangkok for infrastructure and flights, and expect some Bangkok haze.
- A beach and the driest sea: Hua Hin. It is a Gulf town but far drier than the islands, a few hours from Bangkok.
- The Andaman coast: go in the second half of December, or push to January.
- Koh Samui or Koh Phangan: wait for late December at the earliest, and January or February if you can. Koh Lanta against Phuket, Krabi and Koh Phangan from December to March compares the Andaman and Gulf choices.
For a December plan beyond Thailand, our where is warm in December ranking has the dry options across the world, and Bali or Thailand in January picks up where this one ends.
How sure are these numbers?
They are eleven-year month-of-year averages for each place's coordinates: monthly rain totals from CHIRPS (satellite and rain-gauge data), rain days, temperatures and cloud from the Open-Meteo archive. Air-quality figures are model values from 2023 to 2025. A given December can be wetter or drier than the average, and we do not forecast a specific year. Peak-season prices, crowds and sea conditions for boats between islands are not in our data, and Christmas and New Year are expensive on the beaches and in Chiang Mai, so book early. See Data Sources.
Frequently asked questions
Is it dry in Thailand in December?
In Bangkok, Chiang Mai and Hua Hin, yes: 9 mm, 16 mm and 19 mm in our data, with 1 to 2 rainy days. On the Andaman coast it is drying but still has 8 to 10 rainy days, and on the Gulf islands it is still wet, at 318 mm for Koh Samui.
Is Phuket good in December?
Better than November, not yet at its best. Phuket gets 80 mm in December against 213 mm in November, with rain on about 9 of 31 days and a 29°C average high. January (73 mm, about 4 rainy days) is the more reliable month.
Is Koh Samui rainy in December?
Yes. Our data shows 318 mm in December, down from 457 mm in November, with about 10 rainy days. That is about four times Phuket's 80 mm in the same month, and it only drops to 152 mm in January.
Where in Thailand is the weather best in December?
For dry days, Bangkok (9 mm) and Chiang Mai (16 mm). For a beach with the least rain, Hua Hin (19 mm), which is on the Gulf but far drier than the islands. Of the Andaman beaches, Koh Lanta and Phuket are slightly drier than Krabi.
How cold is Chiang Mai in December?
Mild days and cool nights: a 27°C average high and a 17°C average low in our data. Bring a jacket for early mornings, especially on a scooter.
Is Bangkok's air bad in December?
It can be. In our model data for 2023 to 2025 the December average sat above the WHO daily guideline in every year, with several bad days each month. Rain is not the issue in Bangkok in December; haze is.
Is Koh Samui or Phuket better in December?
Phuket, on the numbers. In December Phuket gets 80 mm on about 9 rainy days and Koh Samui gets 318 mm on about 10, so the Gulf island is about four times wetter. Both improve in January (Phuket 73 mm, Koh Samui 152 mm), and Samui is best from February.
Not sure where yet? Pick your months and what to avoid, and get your 3 best places → Where should I go?
Weather data: Open-Meteo (CC BY 4.0), open-meteo.com; rain totals: CHIRPS (Climate Hazards Center, UC Santa Barbara). Processed by NomadWeather from stored copies of the data.