Thailand's 2026 Cold Season Starts Late and Runs Warmer Than Usual

Thailand's cold season is expected to arrive in the coming week, roughly a week later than usual. The Thai Meteorological Department (TMD) says temperatures for the season as a whole will be higher than normal.

When the season runs

In its seasonal outlook, released on October 15, the TMD said temperatures should start to drop around the third week of October. The cool period is forecast to last until about mid-February 2027.

Temperature expectations

Average minimum temperatures are forecast to fall between 22 and 23°C, about two degrees above the usual level. Some northern and northeastern areas, however, could still get much colder.

• Upper North and upper Northeast: minimum temperatures of 10 to 12°C
• Bangkok: lows of 19 to 21°C
• Surrounding provinces: lows of 18 to 20°C

The coldest stretch is expected between late December and early February. Mountain summits, peaks and ridges may see cold to very cold conditions, and frost is possible in some places.

Why it will be warmer

The TMD links the milder outlook to El Niño. The weather pattern is expected to strengthen toward the end of this year and carry into early 2027, which could push temperatures above normal.

Risks in the south and upper regions

Southern Thailand faces a different threat. From November through December, the department warns of heavy rain along the Gulf coast from Chumphon southward, which could bring flash floods, surface runoff and rivers overflowing their banks. Waves in the Gulf could reach 2 to 4 metres, and storm surges of 4 to 5 metres are possible in some spots.

In January and February, the upper part of the country may see thunderstorms, squalls and hail in some areas.

How the forecast was made

The outlook is based on statistical data and climate models. The TMD plans to update it during the final week of October.

Short-term rain warning

Even though cooler weather is expected later in the year, the TMD has issued a separate warning for heavy to very heavy rain in parts of the country from October 18 to 25. From October 18 to 20, persistent rain is forecast for the South and East, with some areas possibly seeing heavy to very heavy downpours.

From October 21 to 25, rainfall is expected to increase across the lower Northeast, Central Thailand (including Bangkok and its metropolitan area), the East and the upper South. Some locations could get heavy to very heavy rain along with occasional gusty winds.

This short-term warning is separate from the longer-range cold-season outlook, and forecasts may change as the TMD releases updates.