Thailand's meteorological department has issued a heavy rain alert for 39 provinces as the southwest monsoon moderates, with northern regions facing the highest risk of flash flooding in foothill areas near waterways.
On July 17, 2025, the Thai Meteorological Department forecasts decreasing rainfall across Thailand over the next 24 hours as the southwest monsoon moderates, covering the Andaman Sea, Thailand, and the Gulf of Thailand. A low-pressure trough remains over northern Vietnam. Residents in northern Thailand are warned of dangers from heavy rainfall and accumulated water, which may trigger flash flooding and flash floods, especially in foothill areas near waterways and depressions. The upper Andaman and upper Gulf of Thailand will have moderate winds with waves 1–2 meters high; the lower Andaman approximately 1 meter, with thunderstorm zones exceeding 2 meters. Sailors should proceed carefully and avoid thunderstorm areas.
Weather forecast for Thailand from 07:00 today to 07:00 tomorrow:
Northern Region: 40% thunderstorm coverage, mainly around Mae Hong Son, Chiang Mai, Chiang Rai, Tak, Phayao, Nan, Phichit, and Phetchabun. Low 22–25°C, high 30–32°C. Southwest wind 10–20 km/h.
Northeastern Region: 30% thunderstorms, mainly Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen, and Ubon Ratchathani. Low 23–26°C, high 31–36°C. Southwest wind 10–20 km/h.
Central Region: 30% thunderstorms, mainly Ayutthaya, Lopburi, Saraburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon. Low 23–26°C, high 33–36°C. Southwest wind 10–20 km/h.
Eastern Region: 40% thunderstorms, mainly Nakhon Nayok, Prachuap Khiri Khan, Chachoengsao, Chanthaburi, and Trat. Low 23–26°C, high 31–34°C. Southwest wind 15–35 km/h. Sea waves 1–2 meters; thunderstorm areas over 2 meters.
Southern Region (East Coast): 30% thunderstorms, mainly Chumphon, Surat Thani, Songkhla, Pattani, Yala, and Narathiwat. Low 23–25°C, high 33–36°C. Southwest wind 15–30 km/h. Sea waves approximately 1 meter, offshore over 1 meter; thunderstorm zones over 2 meters.
Southern Region (West Coast): 30% thunderstorms, mainly Ranong, Phang Nga, Trang, and Satun. Low 23–25°C, high 31–35°C. From Phang Nga northward: Southwest wind 15–35 km/h, waves 1–2 meters, thunderstorm areas over 2 meters. From Phuket southward: Southwest wind 15–30 km/h, waves approximately 1 meter; thunderstorm zones over 2 meters.
Bangkok and Vicinity: 40% thunderstorm coverage. Low 25–26°C, high 33–34°C. Southwest wind 10–20 km/h.