Cold snap all week: temps to drop 1-3°C in upper Thailand, South to see more rain
The Thai Meteorological Department warns of a new cold surge over upper Thailand from Jan 20-25, with temperatures down 1-3°C, while the South faces increasing rain and stronger seas later in the week.
The Thai Meteorological Department (TMD) has issued an advisory warning of a new cold surge affecting upper Thailand throughout the week, with temperatures expected to fall by 1-3°C during January 20-25, 2026, while the South will continue to see rain.
From January 20-25, temperatures in upper Thailand are forecast to drop by 1-3°C, bringing cool to cold conditions. The TMD said this will be driven by a new, moderate high-pressure system (cold air mass) from China spreading over upper Thailand and the South China Sea.
In the South, January 19-20 will bring isolated thundershowers as a weak northeast monsoon covers the Gulf of Thailand, the South and the Andaman Sea. Waves in both the Gulf and the Andaman are expected to be around 1 metre, rising to more than 1 metre in thundershowers.
From January 21-25, rainfall in the South is expected to increase as the northeast monsoon strengthens to a moderate level. Winds and waves in the Gulf will also strengthen. In the lower Gulf of Thailand, waves are forecast at 1-2 metres, exceeding 2 metres in thundershowers.
The TMD advised residents in upper Thailand to take care of their health due to changing weather, and to use extra caution when travelling in foggy areas. Mariners in the Gulf of Thailand and the Andaman Sea were urged to navigate carefully.
