TMD expects gulf coast provinces of isolated heavy rain, five days of heavy southern rain on November 18-22
Heavy rain could trigger flash floods in southern Thailand on November 18–22, with waves above 3 metres in lower Gulf thundershowers.
- The Thai Meteorological Department (TMD) forecasts persistent heavy to very heavy rain in southern Thailand from November 18 to 22.
- Accumulated rainfall may trigger flash floods and rapid run-off, especially on foothill slopes and in low-lying areas.
- During this period, waves in the lower Gulf of Thailand are expected to exceed 3 metres in thundershowers, and mariners are advised to navigate cautiously.
The Thai Meteorological Department (TMD) forecast on November 14, 2026, that southern Thailand would experience persistent rain on November 18–22, with heavy falls in many areas and isolated very heavy rain. Accumulated rainfall could trigger flash floods and rapid run-off, particularly on foothill slopes near waterways and in low-lying areas.
The TMD’s November 14–15 forecast also identifies Prachuap Khiri Khan, Chumphon and Surat Thani among the Gulf coast provinces expecting isolated heavy rain. A moderate northeast monsoon over the Gulf of Thailand and the South continues to bring wet conditions to the region.
Lower Gulf waves may exceed 3 metres on November 18–22
The TMD expects lower Gulf waves of about 2 metres, rising above 3 metres in thundershowers, on November 18–22. Winds and waves are expected to strengthen across the Gulf of Thailand and the Andaman Sea over the same period.
Mariners in the Gulf of Thailand and the Andaman Sea should check their routes, navigate cautiously and avoid areas with thundershowers on November 18–22, the TMD advised.
Upper Thailand warms before cooler weather returns
The TMD expects temperatures to rise across upper Thailand on November 14–15, with rain in some areas. The North and Northeast will retain cool mornings with light mist.
A moderate high-pressure system covers the North, Northeast and South China Sea, according to the TMD. Easterly and southeasterly winds are carrying moisture into the lower Northeast, East and lower Central region.
The TMD’s November 18–22 outlook indicates thundershowers and isolated gusty winds across upper Thailand at the start of the period, followed by cooler conditions and strong winds.
People in upper Thailand should take care of their health as conditions change, while farmers should prepare to protect their crops from possible weather damage, the TMD advised.
Southern coasts expect 60–70% thundershower coverage on November 14–15
The TMD forecasts thundershowers across 70% of the South’s east coast and 60% of its west coast in the bulletin covering 6am on November 14 to 6am on November 15, Thailand time (UTC+7).
The regional forecast is as follows:
- North, November 14–15: Cool mornings with light mist and isolated rain. Minimum temperatures will be 16–22°C and maximum temperatures 28–34°C, while mountaintops will be cold with lows of 10–15°C. Northeasterly winds will reach 10–20 km/h.
- Northeast, November 14–15: Cool mornings with light mist, isolated rain and a temperature rise of 1–2°C. Minimum temperatures will be 19–22°C and maximum temperatures 31–33°C, with cool to cold conditions on mountaintops and lows of 11–17°C. Northeasterly winds will reach 10–20 km/h.
- Central region, November 14–15: Mostly cloudy conditions with isolated rain and a temperature rise of 1–2°C. Minimum temperatures will be 22–25°C and maximum temperatures 31–34°C. Easterly winds will reach 10–20 km/h.
- East, November 14–15: Mostly cloudy conditions with a temperature rise of 1–2°C and rain covering 10% of the region, mainly in Nakhon Nayok, Chon Buri, Rayong, Chanthaburi and Trat. Minimum temperatures will be 23–26°C and maximum temperatures 32–34°C. Easterly winds will reach 15–30 km/h, with waves of about 1 metre, exceeding 1 metre offshore.
- South, east coast, November 14–15: Thundershowers will cover 70% of the region, with isolated heavy rain in Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat. Minimum temperatures will be 22–24°C and maximum temperatures 29–34°C. From Surat Thani northwards, northeasterly winds will reach 15–35 km/h, with waves of 1–2 metres, exceeding 2 metres in thundershowers. From Nakhon Si Thammarat southwards, easterly winds will reach 20–35 km/h, with waves of about 2 metres, exceeding 2 metres in thundershowers.
- South, west coast, November 14–15: Thundershowers will cover 60% of the region, with isolated heavy rain in Ranong, Phang Nga, Trang and Satun. Minimum temperatures will be 23–25°C and maximum temperatures 27–34°C. Easterly winds will reach 15–35 km/h, with waves of about 1 metre, rising to 1–2 metres offshore and exceeding 2 metres in thundershowers.
- Bangkok and surrounding provinces, November 14–15: Mostly cloudy conditions with a temperature rise of 1–2°C and rain covering 10% of the area. Minimum temperatures will be 24–26°C and maximum temperatures 32–34°C. Easterly winds will reach 10–20 km/h.
