December is the start of high season in Thailand: the north, Bangkok and the east are dry, the Andaman coast has dried out since November, and the Gulf islands around Koh Samui are still in their rainy period. Below are Thai Meteorological Department (TMD) normals for ten stations, TMD’s outlook for December 2026, the status of marine national parks, hotel occupancy and events with confirmed dates. Checked on 25 October 2026.
December weather by region: TMD normals
These are 1991-2020 normals from the TMD report; the Krabi station (48 563) has a shorter 1994-2020 record. A rainy day means 0.1 mm or more. Khao Lak uses the nearest TMD station, Takua Pa (individual beaches may differ). Koh Phangan and Koh Tao have no TMD station, so Samui is the nearest reference. Hotel occupancy is from the Ministry of Tourism and Sports (MOTS) for the whole province, not a resort: December 2025, the latest December in the MOTS file.
| Region, TMD station | High, °C | Low, °C | Rain, mm | Rainy days | Hotel occupancy Dec 2025, % |
|---|---|---|---|---|---|
| Phuket (Phuket, 48 564) | 32.1 | 25.0 | 82.0 | 10.3 | 84.10 |
| Khao Lak (Takua Pa, 48 561) | 31.9 | 22.7 | 78.4 | 9.0 | 88.74 (Phang Nga) |
| Krabi (Krabi, 48 563, 1994-2020) | 31.5 | 21.7 | 90.3 | 11.1 | 80.91 |
| Koh Lanta (Ko Lanta, 48 566) | 31.4 | 23.9 | 64.6 | 9.6 | 80.91 (Krabi) |
| Koh Samui, Phangan, Tao (Ko Samui, 48 550) | 29.3 | 24.0 | 263.1 | 14.2 | 83.54 (Surat Thani) |
| Pattaya (Phatthaya, 48 461) | 30.2 | 23.3 | 11.7 | 1.9 | 82.08 (Chon Buri) |
| Hua Hin (Hua Hin, 48 475) | 29.8 | 23.3 | 11.9 | 1.6 | 79.37 (Prachuap Khiri Khan) |
| Bangkok (Bangkok Metropolis, 48 455) | 32.3 | 23.2 | 11.6 | 1.5 | 84.80 |
| Chiang Mai (Chiang Mai, 48 327) | 29.2 | 16.9 | 14.1 | 1.8 | 94.75 |
| Chiang Rai (Chiang Rai, 48 303) | 27.8 | 14.7 | 20.6 | 2.5 | 92.55 |
TMD outlook for December 2026
TMD issued its cool season outlook on 9 October 2026. For December:
| Region | Minimum temperature | Rain |
|---|---|---|
| Upper north | 18-20 °C | light rain in places |
| Bangkok and suburbs | 24-26 °C | light rain in places |
| East including the coast (Pattaya) | 23-25 °C | light rain in places |
| South, Andaman coast (Phuket, Krabi) | 24-26 °C | rain over 10-20% of the area |
| South, Gulf coast (Samui) | 23-25 °C | thunderstorms over 60-80%, heavy to very heavy rain in places, mostly from Surat Thani southwards |
On the Gulf side of the south, from Chumphon southwards, TMD expects heavy rain until early January and waves of 2-4 m at times. The Andaman Sea is expected to have waves of 1-2 m. TMD also warns that in November and December low-pressure areas often form over the South China Sea and may become tropical cyclones that pass near or across the Gulf of Thailand and the south, bringing waves of 3-4 m, up to 4-5 m in places. In the north the coldest spell is expected from late December to early February, with dense fog possible in December and January. TMD expects El Niño to strengthen, so the season may be warmer than usual. It will update the outlook in the last week of October.
Where to go in December
Phuket, Khao Lak, Krabi, Koh Lanta. The rains of November are over: from 64.6 mm on Koh Lanta to 90.3 mm in Krabi, on 9.0-11.1 rainy days, against 178-232 mm in November at Phuket, Krabi and Takua Pa. TMD expects waves of 1-2 m and rain over 10-20% of the Andaman coast. Lanta is the driest of the four. Monthly numbers in Phuket by month.
Koh Samui, Koh Phangan, Koh Tao. Still wet: 263.1 mm on 14.2 days at the Samui station, the highest of the ten stations in the table, though well below November’s 444.6 mm. TMD expects thunderstorms over 60-80% of the area. Ang Thong Marine Park near Samui reopens on 16 December. These islands are drier from February: Samui gets 64.3 mm that month. More on seasons and ferries in the Koh Samui holiday guide.
Pattaya and Hua Hin. Almost rainless: 11.7 mm on 1.9 days and 11.9 mm on 1.6 days, the driest month of the year at both stations. Highs are 30.2 and 29.8 °C, nights 23.3 °C. Guides: Pattaya and Hua Hin.
Bangkok. The driest month of the year in the city: 11.6 mm on 1.5 days, highs of 32.3 °C and nights of 23.2 °C. The Pollution Control Department (PCD) puts Bangkok and its suburbs in the PM2.5 watch period from November to March, so check Air4Thai before long outdoor days. The Bangkok Art Biennale runs until 28 February 2027.
Chiang Mai and Chiang Rai. Cool and dry: highs of 29.2 and 27.8 °C, nights of 16.9 and 14.7 °C, 14.1 and 20.6 mm of rain. December is the busiest month of the year for Chiang Mai hotels (94.75% in December 2025). PCD’s PM2.5 watch period for the north starts in January, see Chiang Mai smoke season.
National parks and islands in December
| Park | Status in December 2026 | Source |
|---|---|---|
| Ang Thong Marine Park (Samui) | closed until 15 December, open from 16 December (annual closure 1 November-15 December) | DNP |
| Similan Islands | open (annual closure 16 May-14 October) | DNP |
| Surin Islands | open (annual closure 16 May-14 October) | DNP |
| Maya Bay, Phi Phi | open (annual closure 1 August-30 September) | DNP |
| Ko Rok (Lanta) | open (annual closure 16 May-15 November) | DNP park page |
The table is from the Department of National Parks (DNP) closure list for 2026, with data as of 7 January 2026. Parks can change their rules, so check with the park before you book a trip. DNP also lists several Similan dive sites and Ko Tachai as closed indefinitely.
Events in December 2026
| Event | 2026 date | Where | Source |
|---|---|---|---|
| Father’s Day and National Day (birthday of King Bhumibol the Great) | Saturday 5 December, bank holiday on Monday 7 December | nationwide | Bank of Thailand |
| Constitution Day | Thursday 10 December | nationwide | Bank of Thailand |
| Tomorrowland Thailand | 11-13 December | Wisdom Valley | Tomorrowland |
| EDC Thailand | 18-20 December | Rhythm Park, Phuket | EDC Thailand |
| New Year’s Eve | Thursday 31 December, bank holiday | nationwide | Bank of Thailand |
| Bangkok Art Biennale | until 28 February 2027 | Bangkok: temples, museums, public spaces | TAT |
Tomorrowland states on its site that Thailand 2026 is sold out. EDC Thailand is at Rhythm Park in Phuket. If your dates overlap with either, book rooms and transfers early. As of 25 October TAT had not published a December calendar or a New Year countdown programme: it published the October calendar on 29 September, and we will add December events when TAT’s calendar appears.
Hotel occupancy in December
MOTS counts occupancy by province, not by resort, and it is not a price. December 2025 was the busiest month of the year in Chiang Mai (94.75%), Bangkok (84.80%), Surat Thani, the province of Samui, Phangan and Tao (83.54%), Chiang Rai (92.55%) and Phang Nga, the province of Khao Lak (88.74%). Phuket was at 84.10%, second only to January. Pattaya’s province, Chon Buri, had 82.08%, Krabi 80.91% and Hua Hin’s province, Prachuap Khiri Khan, 79.37%. We do not publish accommodation prices until we collect our own dated measurements.
Should you go to Thailand in December?
Yes, if you want dry weather in the north, Bangkok, Pattaya and on the Andaman coast and accept high-season crowds. Think again about Koh Samui, Phangan and Tao, where December is still a wet month. If low occupancy matters more than dry weather, look at the shoulder months in Thailand in November, and for what comes next see Thailand in January. How beaches change by region and month is covered in Thailand beaches.
FAQ
Is December a good time to visit Thailand?
For most of the country, yes. By TMD normals Bangkok, Pattaya, Hua Hin and Chiang Mai get 12-14 mm of rain in December, and the Andaman coast has dried out (64.6-90.3 mm). The trade-offs are crowds, since December is the busiest month of the year in Chiang Mai (94.75%), Bangkok (84.80%) and Surat Thani (83.54%), and rain on the Gulf islands (Samui 263.1 mm).
Where is it driest in Thailand in December?
By TMD normals Bangkok (11.6 mm), Pattaya (11.7 mm), Hua Hin (11.9 mm) and Chiang Mai (14.1 mm) get 12-14 mm on 1.5-1.9 rainy days. The Andaman coast gets 64.6 mm on Koh Lanta to 90.3 mm in Krabi.
Is it rainy on Koh Samui in December?
Often, yes. The Samui station records 263.1 mm on 14.2 days in December. TMD expects thunderstorms over 60-80% of the area from Surat Thani southwards in December 2026, and waves of 2-4 m at times until early January. February to April is drier.
Is Ang Thong Marine Park open in December?
Not before 16 December. The DNP closure table for 2026 lists all tourist sites and accommodation in the park as closed from 1 November to 15 December. The table is dated 7 January 2026, so confirm with the park before booking.
How cold is Chiang Mai in December?
TMD normals give 29.2 °C by day and 16.9 °C at night at the Chiang Mai station. TMD expects minimum temperatures of 18-20 °C in the upper north in December 2026, in a cool season about 2 degrees warmer than the norm, with the coldest spell from late December to early February. Mountain tops can be much colder.
Which public holidays fall in Thailand in December 2026?
The Bank of Thailand lists Saturday 5 December (Father's Day and National Day, the birthday of King Bhumibol the Great) with a substitute bank holiday on Monday 7 December, Constitution Day on Thursday 10 December and New Year's Eve on Thursday 31 December.
Sources
- TMD. Climatological Data for the Period 1991-2020 (stations 48 303, 48 327, 48 455, 48 461, 48 475, 48 550, 48 561, 48 563, 48 564, 48 566)
- TMD. Cool season outlook 2026-2027 (issued 9 October 2026), PDF pp. 1-4
- MOTS. Tourism statistics by province 2025 (xlsx)
- DNP. National park closures 2026 (data as of 7 January 2026)
- DNP. Mu Ko Lanta National Park (Ko Rok season)
- Bank of Thailand. Financial institutions holidays 2026
- Tomorrowland Thailand 2026. Official site
- EDC Thailand 2026. Hours and info
- TAT. Bangkok Art Biennale 2026 (29 October 2026 to 28 February 2027)
- TAT. October event and calendar 2026 (published 29 September 2026)
- PCD. Regional PM2.5 risk periods, 10 August 2026
Found an error or outdated fact? Tell the editors, we will fix it and update the check date.