Thailand officially entered the cold season on Monday, the Meteorological Department said. 

The season’s arrival is characterised by the temperature falling below 23°C continuously in upper parts of the country, easterly or northeasterly winds at low altitude and westerly winds at high altitude, and rainfall declining in upper parts of the country.

This year the season came later than usual as it normally starts in mid- or late-October. It started on Oct 23 in 2025.

According to the department, weather fluctuations and changing wind directions in 2026 resulted in the rain continuing, delaying the onset of the cold season.

The coldest period is expected from late December to early February. There could be morning frost on mountaintops. The cold season should end in mid-February.

On Monday, the department said a decrease in temperature by 3-5°C is likely in the Northeast and by 1-3°C in the North, East and Central Plains, including Bangkok and vicinity.

In the South, continuous rain with scattered heavy rain is forecast until Friday.