Monsoon strengthens in the South as colder, windier weather grips upper Thailand

The Thai Meteorological Department has issued its forecast for December 25, 2025, warning that the northeast monsoon is strengthening, bringing more rain across the South and heavy falls in some areas, while upper Thailand remains cold, with a sharp temperature drop expected in the Northeast.

Over the next 24 hours, the lower South is forecast to see increased rainfall, with heavy rain in some places, especially in Phatthalung, Songkhla, Pattani, Yala and Narathiwat. Residents are urged to beware of flash floods and run-off, particularly in foothill areas near waterways and low-lying ground.

At sea, conditions are expected to be moderate to rough. Waves in the lower Gulf of Thailand are forecast at around 2 metres, while the upper Gulf should see waves of 1–2 metres, rising to around 2 metres in thunderstorms. Mariners in the Gulf of Thailand and the Andaman Sea are advised to navigate with caution and avoid stormy areas.

In upper Thailand, temperatures are expected to fall with stronger winds as another fairly strong high-pressure system, or cold air mass, from China moves south and is forecast to cover upper Thailand today. People are advised to take care of their health in colder conditions and to remain alert to fire hazards due to dry, windy weather.

The weather forecast for the next 24 hours is as follows:

North: Morning cool with fog. Minimum temperature 16-20 °C. Maximum temperature 30-35 °C. Cold to very cold with isolated frost on mountain tops: minimum temperatures of 4-12 °C. Northeasterly winds 10-20 km/hr.

Northeast: Morning cool to cold with strong winds and 2-4 °C drop in temperature. Minimum temperature 15-22 °C. Maximum temperature 29-34 °C. Cold on mountain tops: minimum temperatures of 12-15 °C. Northeasterly winds 15-30 km/hr.

Central: Morning cool with strong winds and 1-3 °C drop in temperature. Minimum temperature 18-22 °C. Maximum temperature 34-35 °C. Northeasterly winds 10-30 km/hr.

East: Morning cool with strong winds and 1-2 °C drop in temperature. Minimum temperature 20-23 °C. Maximum temperature 32-35 °C. Northeasterly winds 15-30 km/hr. Wave height about 1 metre and 1-2 metres offshore.

South (East Coast): Scattered thundershowers mostly in Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, and Narathiwat. Minimum temperature 22-24 °C. Maximum temperature 32-34 °C. From Nakhon Si Thammarat upward: Northeasterly winds 15-35 km/hr. Wave height 1-2 metres and above 2 metres in thundershower. From Songkhla downward: Northeasterly winds 20-35 km/hr. Wave height about 2 metres and above 2 metres in thundershower.

South (West Coast): Partly cloudy. Isolated thundershowers mostly in Trang and Satun. Minimum temperature 22-23 °C. Maximum temperature 32-34 °C. Northeasterly winds 15-30 km/hr. Wave height about 1 metre, above 1 metre offshore and above 2 metres in thundershower.

Bangkok Metropolitan: Morning cool with strong winds and 1-2 °C drop in temperature. Minimum temperature 22-23 °C. Maximum temperature 34-35 °C. Northeasterly winds 10-30 km/hr.