Thailand's Cool Season Begins: Temperatures Drop Across the Country
Thailand has officially entered its cool season, with the Thai Meteorological Department (TMD) announcing the seasonal transition on November 9, 2026. Temperatures are beginning to fall across the northern and northeastern regions, while much of central and southern Thailand remains considerably warmer. The annual change in weather also brings renewed attention to air quality, as the country approaches the dry season.
Thailand Officially Enters Its Cool Season
The Thai Meteorological Department announced that Thailand’s 2026–2027 cool season began on November 9 and is expected to continue until late February 2027.
The seasonal transition is associated with the arrival of cooler air masses from China and a change in prevailing wind patterns, with the northeast monsoon becoming more established. Rainfall is also expected to decrease across much of upper Thailand.
However, the official start of the cool season does not mean that cold weather immediately reaches every part of the country. Conditions vary considerably between regions, and daytime temperatures can remain high even when mornings become noticeably cooler. It is, therefore, a month of November that is relatively milder than in other years.
According to the TMD’s seasonal outlook, January 2027 is expected to be the coldest month of the season, particularly in northern and northeastern Thailand.
The department forecasts that temperatures in the upper North and Northeast could fall to around 10–13°C during the coldest periods. In Chiang Rai, minimum temperatures could reach 9–11°C, while Bangkok is expected to experience lows of approximately 19–21°C.
This is the perfect time to visit Bangkok and many other regions. It is also the favorite time of year for many Thai people, who appreciate the drop in temperatures—especially at night—which allows them to turn off their air conditioning!
Temperatures Drop Across Northern and Northeastern Thailand
The first significant changes are already being felt in northern and northeastern Thailand. A relatively strong high-pressure system moving south from China is bringing cooler air and stronger winds to upper Thailand.
For November 9–13, 2026, the TMD forecast a temperature decrease of:
| Region | Expected temperature drop |
|---|---|
| Northeast | 3–5°C |
| North | 2–4°C |
| Central Thailand | 1–3°C |
| Eastern Thailand | 1–3°C |
| Bangkok and surrounding areas | 1–2°C |
During this period, minimum temperatures are expected to range between 17 and 23°C in the Northeast and between 17 and 23°C in the North. Mountain areas will be considerably cooler, with minimum temperatures potentially reaching 8–15°C in the North and 9–14°C in the Northeast.
These conditions make the cool season one of the most popular times to explore destinations such as Chiang Mai, Chiang Rai, Mae Hong Son and Loei.
For visitors planning early-morning excursions or sunrise trips into the mountains, packing a warm layer is advisable. Temperatures can be surprisingly low before sunrise, even when afternoons remain warm.
Air Pollution: A Concern as the Dry Season Approaches
The arrival of the cool season also marks a gradual change in atmospheric conditions. As rainfall decreases across upper Thailand, the risk of fine particulate pollution, particularly PM2.5, becomes an important issue to monitor.
Northern Thailand, especially the Chiang Mai area, regularly faces seasonal air pollution associated with agricultural burning, forest fires and other sources of particulate matter.
However, the beginning of the 2026–2027 cool season does not automatically mean that pollution levels are rising. Current air-quality readings do not yet indicate a widespread deterioration across the country.
The situation will need closer monitoring over the coming weeks, particularly as the dry season progresses and agricultural burning becomes more relevant.
Travellers can check current pollution levels through Air4Thai, the air-quality monitoring platform operated by Thailand’s Pollution Control Department, before planning outdoor activities.
Thailand’s Coldest Temperatures: A Record of –1.4°C
Thailand is generally associated with tropical heat rather than freezing temperatures. Yet the country’s historical weather records tell a rather different story.
According to historical figures attributed to the Thai Meteorological Department, the country’s lowest recorded temperature was –1.4°C, measured in Sakon Nakhon on January 2, 1974.
This is particularly surprising because the record was registered in northeastern Thailand, rather than on one of the country’s highest mountain peaks.
Loei also recorded an exceptionally low temperature of –1.3°C on the same morning, according to historical figures reproducing the TMD statistics.
| Location | Recorded minimum | Date |
|---|---|---|
| Sakon Nakhon | –1.4°C | January 2, 1974 |
| Loei | –1.3°C | January 2, 1974 |
These figures are historical station records, not typical winter temperatures. They also illustrate how cold air can occasionally affect the inland Northeast during particularly strong winter outbreaks.
Has It Ever Snowed in Thailand?
It is a question that regularly comes up during the cool season: has Thailand ever experienced snowfall?
There is no officially documented snowfall in the country’s meteorological records. However, northern Thailand does occasionally experience a remarkable winter phenomenon known as mae khaning, the Thai term for ground frost or hoarfrost.
This occurs when temperatures fall sufficiently low for ice crystals to form on grass, leaves and other exposed surfaces, usually during the early morning.
One of the best-known places to witness this phenomenon is Doi Inthanon, in Chiang Mai province. Rising to 2,565 metres above sea level, it is Thailand’s highest mountain and a popular destination during the cool season.
When frost covers the vegetation, the landscape can appear almost snow-covered. Despite appearances, however, this is frost rather than snowfall.
For visitors hoping to experience a different side of tropical Thailand, an early-morning trip into the northern mountains can offer a memorable glimpse of the country’s colder climate.
FAQ: Thailand’s Cool Season and Winter Weather
When does the cool season start in Thailand in 2026?
The Thai Meteorological Department officially announced the start of the 2026–2027 cool season on November 9, 2026. It is expected to last until late February 2027, with January forecast to be the coldest month.
Which part of Thailand gets the coldest weather?
Northern and northeastern Thailand generally experience the lowest temperatures. Mountain areas around Chiang Mai and Chiang Rai can become particularly cold during the early morning, sometimes approaching freezing conditions.
What is the coldest temperature ever recorded in Thailand?
The historical national record is –1.4°C, recorded in Sakon Nakhon on January 2, 1974, according to figures attributed to the Thai Meteorological Department.
Does it ever snow in Thailand?
No officially documented snowfall appears in Thailand’s meteorological records. However, ground frost, known locally as mae khaning, sometimes forms on high mountain peaks in the North.
Is Bangkok cold during the Thai winter?
Bangkok generally remains warm throughout the cool season. For the 2026–2027 season, the TMD forecasts minimum temperatures of around 19–21°C during the coldest periods.
Is November a good time to visit northern Thailand?
Yes. November marks the beginning of the cool season, making it an increasingly popular time to visit Chiang Mai, Chiang Rai and the northern mountains. However, weather conditions can still vary, so checking local forecasts before travelling is recommended.
Sources:
- Thai Meteorological Department (TMD): 2026–2027 cool-season announcement and seasonal forecast.
- Thai Meteorological Department: Historical minimum temperature statistics.
- Pollution Control Department: Air4Thai air-quality monitoring platform.
