Thai weather agency outlines 3 winter criteria for 2026
Thailand’s winter declaration depends on minimum temperatures below 23°C, changing winds and declining rainfall, with the 2026 start date unconfirmed.
- Minimum temperatures must fall below 23°C to be considered cool weather.
- Prevailing winds must shift to come from the northeast or east over the country.
- Rainfall and its coverage must continuously decrease, especially in upper Thailand.
The Thai Meteorological Department (TMD) has outlined three conditions used to determine the start of Thailand’s winter season, stressing that cooler weather alone does not signal its official arrival. The start date for the 2026 season remains subject to a formal announcement.
The TMD explained that a winter declaration depends on an assessment of the broader weather pattern, covering temperature, prevailing winds and rainfall.
The three criteria are:
- Cooler temperatures: Minimum temperatures fall below 23°C, bringing conditions into the cool-weather range.
- Changing winds: Northeasterly or easterly winds prevail over Thailand.
- Declining rainfall: Rainfall and its coverage decrease continuously, particularly in upper Thailand.
Thailand’s winter normally begins around mid-October and ends around mid-February of the following year. That usual seasonal pattern does not establish the official start date for 2026.
The TMD advises the public to follow its announcements for confirmation of when this year’s winter season begins.
