Nationwide rainfall declines while upper Thailand faces heavy rain
People in upper Thailand are warned of flash floods from heavy and accumulated rain, while waves could exceed two metres during thunderstorms.
- The Thai Meteorological Department forecasts a nationwide decrease in rainfall over the next 24 hours due to a moderate southwest monsoon.
- Despite the overall decline, upper Thailand is expected to experience heavy and accumulated rain, prompting warnings of potential flash floods and forest run-off.
- Moderate wind and waves of 1-2 metres are predicted for the upper Andaman Sea and the upper Gulf of Thailand, with mariners advised to be cautious.
- Thunderstorms are forecast across 30-40% of most regions, with specific provinces in the North, Northeast, Central, and East identified as likely to be affected.
The Thai Meteorological Department (TMD) forecast less rain across Thailand over the next 24 hours on Friday (July 17, 2026), as a moderate southwest monsoon prevailed over the Andaman Sea, Thailand and the Gulf of Thailand, while a low-pressure cell covered upper Vietnam.
People in upper Thailand were advised to beware of heavy and accumulated rain, which could cause flash floods and forest run-off, particularly on slopes near waterways and in low-lying areas.
Moderate wind and waves were forecast in the upper Andaman Sea and the upper Gulf of Thailand, with waves 1–2 metres high.
The lower Andaman Sea was expected to have waves of about 1 metre, rising above 2 metres during thunderstorms.
Mariners were advised to proceed with caution and avoid areas affected by thunderstorms.
Weather forecast for Thailand from 7am on Friday (July 17) to 7am on Saturday (July 18)
Northern region
- Thunderstorms are forecast across 40% of the region, mainly in Mae Hong Son, Chiang Mai, Chiang Rai, Tak, Phayao, Nan, Phitsanulok and Phetchabun.
- Minimum temperatures will range from 22–25°C and maximum temperatures from 30–32°C, with southwesterly winds of 10–20 km/h.
Northeastern region
- Thunderstorms are forecast across 30% of the region, mainly in Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani.
- Minimum temperatures will range from 23–26°C and maximum temperatures from 31–36°C, with southwesterly winds of 10–20 km/h.
Central region
- Thunderstorms are forecast across 30% of the region, mainly in Phra Nakhon Si Ayutthaya, Lop Buri, Saraburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram and Samut Sakhon.
- Minimum temperatures will range from 23–26°C and maximum temperatures from 33–36°C, with southwesterly winds of 10–20 km/h.
Eastern region
- Thunderstorms are forecast across 40% of the region, mainly in Nakhon Nayok, Prachinburi, Chachoengsao, Chanthaburi and Trat.
- Minimum temperatures will range from 23–26°C and maximum temperatures from 31–34°C, with southwesterly winds of 15–35 km/h.
- Waves will be 1–2 metres high and exceed 2 metres during thunderstorms.
Southern region (east coast)
- Thunderstorms are forecast across 30% of the region, mainly in Chumphon, Surat Thani, Songkhla, Pattani, Yala and Narathiwat.
- Minimum temperatures will range from 23–25°C and maximum temperatures from 33–36°C, with southwesterly winds of 15–30 km/h.
- Waves will be about 1 metre high, exceeding 1 metre offshore and 2 metres during thunderstorms.
Southern region (west coast)
- Thunderstorms are forecast across 30% of the region, mainly in Ranong, Phang Nga, Trang and Satun.
- Minimum temperatures will range from 23–25°C and maximum temperatures from 31–35°C.
- From Phang Nga northwards, southwesterly winds will reach 15–35 km/h, with waves of 1–2 metres and above 2 metres during thunderstorms.
- From Phuket southwards, southwesterly winds will reach 15–30 km/h, with waves of about 1 metre and above 2 metres during thunderstorms.
Bangkok and the surrounding provinces
- Thunderstorms are forecast across 40% of the area.
- Minimum temperatures will range from 25–26°C and maximum temperatures from 33–34°C, with southwesterly winds of 10–20 km/h.
