Cooler weather is forecast for the North, Northeast, Central and East with temperatures expected to drop 3-5°C through to Sunday.
The Meteorological Department said on Thursday morning that another strong high-pressure system from China would cover upper Thailand from Dec 3 to Dec 5. The weather would be cool to cold with strong winds.
Temperatures in the Northeast, North, Central and East would fall 3-5°C, and mountain tops in the North and Northeast could expect morning lows of 3-12°C.
The department advised people in upper Thailand to take care of their health, which could be affected by weather changes.