Rainfall above 90mm forecast for parts of northern Thailand
Residents in at-risk northern areas are urged to monitor conditions as accumulated rain may trigger flash floods, forest run-off, mudslides and waterlogging.
- A heavy rain watch is in effect for northern Thailand from August 6 to 8, with some areas forecast to receive rainfall exceeding 90mm.
- On Friday, August 7, an orange warning for over 90mm of rain is issued for the Thung Chang and Song Khwae districts in Nan province.
- The orange warning for over 90mm of rain continues on Saturday, August 8, for districts in Chiang Rai (Wiang Chai, Phan) and Phitsanulok (Chat Trakan).
- Authorities warn that the heavy rainfall could cause flash floods and mudslides, advising residents in at-risk areas to take precautions.
The Office of the National Water Resources Region 1 (ONWR Region 1) has issued a heavy-rain watch for northern Thailand from August 6 to 8.
Accumulated rainfall could cause flash floods, forest run-off, mudslides and waterlogging in low-lying areas.
Residents in at-risk areas have been advised to monitor conditions closely.
Daily at-risk areas
Thursday (August 6, 2026)
Yellow watch areas with rainfall of 35-90 millimetres cover 12 provinces:
- Chiang Mai: Omkoi, Wiang Haeng, Chai Prakan, Chiang Dao and Fang districts
- Uttaradit: Tha Pla, Ban Khok and Fak Tha districts
- Phrae: Long, Song, Wang Chin and Nong Muang Khai districts
- Nan: Mae Charim, Tha Wang Pha, Thung Chang, Chiang Klang, Song Khwae and Chaloem Phra Kiat districts
- Phayao: Chun, Chiang Kham, Dok Khamtai, Pong and Phu Sang districts
- Chiang Rai: Mae Chan, Wiang Kaen and Mae Fa Luang districts
- Mae Hong Son: Sop Moei district
- Tak: Mueang Tak, Mae Ramat, Tha Song Yang, Umphang and Wang Chao districts
- Kamphaeng Phet: Mueang Kamphaeng Phet, Khlong Lan, Khlong Khlung, Pang Sila Thong and Kosamphi Nakhon districts
- Phitsanulok: Nakhon Thai, Wat Bot and Wang Thong districts
- Phichit: Wang Sai Phun district
- Nakhon Sawan: Takhli, Tha Tako, Phayuha Khiri and Tak Fa districts
Friday (August 7, 2026)
The warning level is raised for very heavy rain in some areas.
Orange warning areas with rainfall exceeding 90 millimetres:
- Nan: Thung Chang and Song Khwae districts
Yellow warning areas with rainfall of 35-90 millimetres extend across 14 provinces:
- Sukhothai: Mueang Sukhothai and Si Satchanalai districts
- Lampang: Ngao, Chae Hom and Thoen districts
- Phetchabun: Mueang Phetchabun, Lom Sak and Khao Kho districts
- Chiang Mai
- Chiang Rai
- Mae Hong Son
- Uttaradit
- Phrae
- Phayao
- Kamphaeng Phet
- Tak
- Phitsanulok
- Phichit
- Nakhon Sawan
Saturday (August 8, 2026)
The heavy-rain watch remains in effect.
Orange warning areas with rainfall exceeding 90 millimetres:
- Chiang Rai: Wiang Chai and Phan districts
- Phitsanulok: Chat Trakan district
Yellow warning areas with rainfall of 35-90 millimetres:
- Chiang Mai: Mueang Chiang Mai, Mae Chaem and Chiang Dao districts
- Mae Hong Son: Pai and Khun Yuam districts
- Chiang Rai
- Lampang
- Sukhothai
- Kamphaeng Phet
- Uttaradit
- Nan
- Phayao
- Nakhon Sawan
- Tak
Guidance for the public
Although total rainfall accumulated over the three days is no more than 150 millimetres, accumulated rain in foothill and low-lying areas could cause water to surge rapidly. Residents are advised to prepare as follows:
- Check drainage channels around homes and ensure they are free from obstructions.
- Move belongings to higher ground, particularly for people living near waterways and at the foot of hills.
- Avoid routes affected by standing floodwater or at risk of landslides.
- Follow news and weather conditions closely through the National Hydroinformatics Data Centre website.
