The Thai Meteorological Department’s Announcement No. 20 warns of heavy to very heavy rain and strong waves in the Gulf of Thailand and Andaman Sea until December 16, while upper Thailand will see thunderstorms and a 2-4°C temperature drop under a strong high-pressure system from China.
The Thai Meteorological Department (TMD) has issued Announcement No. 20 warning of heavy to very heavy rain in the South and strong winds and high waves in the Gulf of Thailand, with impacts expected through to December 16, 2025. Upper Thailand will experience unsettled weather, with thunderstorms and a 2-4°C drop in temperature.
Between 14-16 December 2025, the lower South will continue to see widespread heavy rain, particularly in the provinces of:
- Nakhon Si Thammarat
- Phatthalung
- Songkhla
- Pattani
- Yala
- Narathiwat
- Krabi
- Trang
- Satun
This is due to a strengthening north-easterly monsoon prevailing over the Gulf of Thailand and the South.
Winds and waves will intensify in both the Gulf of Thailand and the Andaman Sea:
- Lower Gulf of Thailand: waves 2-3 metres high, and over 3 metres in areas with thunderstorms
- Upper Gulf of Thailand: waves around 2 metres
- Andaman Sea (offshore): waves over 2 metres, and higher than 2 metres in thunderstorms
The TMD advises:
- People in the South should beware heavy to very heavy rain and accumulated rainfall, which may cause flash floods and runoff, especially in foothill areas, near waterways and in low-lying areas.
- Mariners in the Gulf of Thailand and the Andaman Sea should proceed with great caution and avoid sailing in areas affected by thunderstorms.
- Small boats in the lower Gulf should stay ashore.
- In upper Thailand, the weather will be unsettled:
- On December 13, isolated thunderstorms are expected as an easterly wind brings moisture over northern and central parts of the country.
- Thereafter, temperatures will drop by 2-4°C, bringing cool to cold conditions and strong winds.
This is due to a rather strong high-pressure system / cold air mass from China spreading over Thailand.
The TMD advises:
- People in upper Thailand should take care of their health due to changing weather.
- Farmers should prepare to protect crops and livestock from potential damage caused by cooler temperatures and strong winds.
The public is urged to follow further announcements from the Thai Meteorological Department and can obtain updated information 24 hours a day via: