The Meteorological Department forecasts the 7-day weather outlook: temperatures in upper Thailand will rise before dropping again to cold conditions during 14-16 December. This time, the cold will last for an extended period.
On 11 December 2025, the Meteorological Department predicts general weather from 10 to 16 December 2025, stating that from 11 to 13 December, upper Thailand will experience rising temperatures with morning fog. However, cool to cold weather will remain in the upper North and upper Northeast because the moderate high-pressure area or cold air mass covering upper Thailand will weaken. Meanwhile, easterly winds will bring moisture over upper Thailand, causing isolated rain and thunderstorms in some areas.
Then, during 14 to 16 December, upper Thailand will cool down with cold to very cold weather and strong winds. In the Northeast, temperatures will drop by 3 to 5 degrees Celsius.
In the North, Central, and Eastern regions, temperatures will decrease by 2 to 4 degrees Celsius as a new high-pressure area or cold air mass from China spreads over upper Thailand.
For the South from 11 to 13 December, rain will increase with heavy showers in many areas including Prachuap Khiri Khan and Chumphon provinces. Very heavy rain is expected in Surat Thani, Nakhon Si Thammarat, Phatthalung, and Songkhla provinces due to a low-pressure cell moving over the South.
From 14 to 16 December, the lower South will continue to experience heavy rain in many areas including Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, and Narathiwat provinces as the northeast monsoon intensifies over the Gulf of Thailand and the South. Waves in the Gulf of Thailand and the Andaman Sea will strengthen: the lower Gulf will have waves 2–3 meters high, with thunderstorms causing waves over 3 meters. The upper Gulf will have waves about 2 meters high, with thunderstorms causing waves over 2 meters. The Andaman Sea will have waves 1–2 meters high offshore and over 2 meters where thunderstorms occur.
Meanwhile, from 11 to 13 December 2025, a low-pressure cell in the lower South China Sea will pass over the southern tip of Vietnam, the Gulf of Thailand, and the South, causing heavy rain in many areas of the South with some places experiencing very heavy rain.
Precautions: People in upper Thailand are advised to take care of their health due to changing weather conditions from 11 to 16 December. Farmers in upper Thailand should prepare to protect and prevent damage to agricultural products. Residents in upper Thailand should beware of dangers from thunderstorms. In the South, be cautious of heavy to very heavy rain and accumulated rainfall that may cause flash floods and landslides, especially in foothill areas near waterways and low-lying zones. Fishermen in the Gulf of Thailand and Andaman Sea should navigate cautiously and avoid sailing in areas with thunderstorms.
, "Meteorological Department" also forecasts that “This round is a warm-up for the cold. The next round will be intense and prolonged, starting from 15 December onward.”
Reference: Meteorological Department