TMD lists provinces facing downpours across upper Thailand

The Thai Meteorological Department (TMD) issued a weather advisory on Monday (August 17, 2026).

It forecast heavy to very heavy rain across upper Thailand from Tuesday (August 18) to Friday (August 21).

The provinces expected to be affected are listed below.

Tuesday (August 18)

Provinces forecast to receive very heavy rain

• Northeast: Bueng Kan and Nakhon Phanom
• East: Trat

Provinces forecast to receive heavy rain

• North: Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Lampang, Phrae and Tak
• Northeast: Nong Khai, Udon Thani, Sakon Nakhon, Kalasin, Mukdahan, Roi Et, Yasothon, Amnat Charoen, Surin, Si Sa Ket and Ubon Ratchathani
• Central: Kanchanaburi and Saraburi
• East: Nakhon Nayok and Chanthaburi

Wednesday (August 19)

Provinces forecast to receive very heavy rain

• North: Chiang Mai, Chiang Rai, Phayao, Nan, Phrae and Lampang
• Northeast: Nong Khai, Bueng Kan, Nakhon Phanom, Sakon Nakhon, Mukdahan and Kalasin
• East: Trat

Provinces forecast to receive heavy rain

• North: Mae Hong Son, Lamphun, Uttaradit, Sukhothai, Tak, Phitsanulok and Phetchabun
• Northeast: Loei, Nong Bua Lam Phu, Udon Thani, Khon Kaen, Roi Et, Yasothon, Amnat Charoen, Si Sa Ket and Ubon Ratchathani
• Central: Saraburi, Kanchanaburi and Ratchaburi
• East: Nakhon Nayok, Prachin Buri and Chanthaburi

Thursday (August 20)

Provinces forecast to receive very heavy rain

• North: Mae Hong Son, Chiang Mai, Lampang, Phayao, Nan, Phrae, Uttaradit and Tak
• Northeast: Bueng Kan, Sakon Nakhon and Nakhon Phanom

Central: Kanchanaburi

• East: Trat

Provinces forecast to receive heavy rain

• North: Chiang Rai, Lamphun, Sukhothai, Kamphaeng Phet, Phichit, Phitsanulok and Phetchabun
• Northeast: Loei, Nong Khai, Nong Bua Lam Phu, Udon Thani, Chaiyaphum, Khon Kaen, Kalasin, Mukdahan, Nakhon Ratchasima, Maha Sarakham, Roi Et, Yasothon, Amnat Charoen and Ubon Ratchathani
• Central: Nakhon Sawan, Uthai Thani, Chai Nat, Lop Buri, Saraburi and Ratchaburi
• East: Nakhon Nayok, Prachin Buri, Sa Kaeo and Chanthaburi

Friday (August 21)

Provinces forecast to receive very heavy rain

• North: Mae Hong Son, Chiang Mai, Phayao, Nan and Tak

Provinces forecast to receive heavy rain

• North: Chiang Rai, Lamphun, Lampang, Phrae, Uttaradit, Sukhothai, Kamphaeng Phet, Phitsanulok and Phetchabun
• Northeast: Loei, Nong Khai, Bueng Kan, Nong Bua Lam Phu, Udon Thani, Sakon Nakhon and Nakhon Phanom
• Central: Nakhon Sawan, Uthai Thani, Kanchanaburi and Ratchaburi
• East: Chanthaburi and Trat

Thailand is forecast to experience isolated heavy to very heavy rain from Tuesday (August 18) to Friday (August 21), particularly in the North and Northeast.

A monsoon trough will extend across the North and upper Northeast, while the southwest monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand will become rather strong.

People in the affected areas should beware of heavy to very heavy rain and accumulated rainfall, which may cause flash floods and forest run-off, especially on foothill slopes near waterways and in low-lying areas.

Travel should be avoided on routes prone to repeated flooding, particularly in low-lying areas where short-term inundation may occur.

Winds and waves in the upper Andaman Sea are expected to become rather strong from Tuesday (August 18) to Friday (August 21).

Waves will be 2-3 metres high and above 3 metres in thundershowers.

In the lower Andaman Sea and upper Gulf of Thailand, waves will be about 2 metres high and above 2 metres in thundershowers.

All vessels in the Andaman Sea and Gulf of Thailand should proceed with caution and avoid areas of thundershowers.

Small boats in the upper Andaman Sea should remain ashore during the period.

For safety and to reduce potential impacts, the public should plan daily activities and travel carefully during the period.

People should follow TMD announcements and can obtain information from the department’s website or by calling 0-2399-4012-13 or 1182, 24 hours a day.

TMD forecast for Thailand from 6pm on Monday (August 17) to 6pm on Tuesday (August 18)

North

• Thundershowers across 60% of the region, with isolated heavy rain in Mae Hong Son, Nan, Tak, Uttaradit and Phrae
• Minimum temperature: 24-28°C
• Maximum temperature: 32-35°C
• Southwesterly winds: 10-20 km/h

Northeast

• Thundershowers across 30% of the region, with isolated heavy rain in Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani
• Minimum temperature: 25-26°C
• Maximum temperature: 34-36°C
• Southwesterly winds: 10-20 km/h

Central region

• Thundershowers across 40% of the region, mainly in Nakhon Sawan, Uthai Thani, Kanchanaburi, Ratchaburi and Saraburi
• Minimum temperature: 24-27°C
• Maximum temperature: 34-37°C
• Southwesterly winds: 10-25 km/h

East

• Thundershowers across 40% of the region, with isolated heavy rain in Chanthaburi and Trat
• Minimum temperature: 24-28°C
• Maximum temperature: 32-35°C
• Southwesterly winds: 20-35 km/h
• Waves about 2 metres high and above 2 metres in thundershowers

South (east coast)

• Thundershowers across 40% of the region, mainly in Prachuap Khiri Khan, Chumphon, Surat Thani and Nakhon Si Thammarat
• Minimum temperature: 23-26°C
• Maximum temperature: 34-36°C
• Southwesterly winds: 15-35 km/h
• Waves 1-2 metres high, about 2 metres offshore and above 2 metres in thundershowers

South (west coast)

• Thundershowers across 60% of the region, with isolated heavy rain in Ranong and Phang Nga
• Minimum temperature: 23-25°C
• Maximum temperature: 31-35°C
• From Ranong northwards: southwesterly winds at 20-35 km/h, with waves about 2 metres high and above 2 metres in thundershowers
• From Phang Nga southwards: southwesterly winds at 15-35 km/h, with waves 1-2 metres high and above 2 metres in thundershowers

Bangkok and vicinity

• Thundershowers across 60% of the area, with isolated heavy rain
• Minimum temperature: 25-28°C
• Maximum temperature: 33-35°C
• Southwesterly winds: 10-25 km/h