Heavy rain warning for 48 provinces as Bangkok braces for downpours

The Thai Meteorological Department has warned of unsettled weather as the south-west monsoon continues to prevail, bringing heavy rain to 48 provinces across Thailand, including Bangkok. Some areas are at risk of forest run-off and flash floods, especially low-lying areas, while boat operators are advised to beware of strong waves.

On June 20, 2026, the Thai Meteorological Department forecast that over the next 24 hours, the East, Bangkok and surrounding provinces, and the lower South would see heavy rain in some areas.

This is due to a moderate south-west monsoon still prevailing over the Andaman Sea, Thailand and the Gulf of Thailand, combined with a low-pressure cell covering upper Vietnam.

People in the affected areas are advised to prepare for heavy rain and accumulated rainfall, which could trigger flash floods and forest run-off, especially in risk areas near waterways and low-lying zones.

Waves in the upper Andaman Sea are moderate at 1-2 metres high. In the lower Andaman Sea and the Gulf of Thailand, waves are about one metre high. In thunderstorm areas, waves may rise above two metres.

Boat operators in the Andaman Sea and the Gulf of Thailand are advised to navigate with caution and avoid sailing in thunderstorm areas.

Weather forecast for Thailand from 6am today to 6am tomorrow

North

• Thunderstorms are expected in 40% of the area, mostly in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Tak, Kamphaeng Phet and Phetchabun.
• Minimum temperature: 23-26°C
• Maximum temperature: 32-35°C
• South-westerly winds: 10-20 km/h

Northeast

• Thunderstorms are expected in 40% of the area, mostly in Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Nakhon Ratchasima and Buri Ram.
• Minimum temperature: 23-25°C
• Maximum temperature: 33-36°C
• South-westerly winds: 10-20 km/h

Central

• Thunderstorms are expected in 40% of the area, mostly in Uthai Thani, Phra Nakhon Si Ayutthaya, Lop Buri, Saraburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram and Samut Sakhon.
• Minimum temperature: 23-26°C
• Maximum temperature: 34-36°C
• South-westerly winds: 10-20 km/h

East

• Thunderstorms are expected in 60% of the area, with heavy rain in some places, especially in Nakhon Nayok, Prachin Buri, Chachoengsao, Chon Buri, Rayong, Chanthaburi and Trat.
• Minimum temperature: 23-26°C
• Maximum temperature: 32-36°C
• South-westerly winds: 15-30 km/h
• Waves about one metre high, and above two metres in thunderstorm areas.

South (East Coast)

• Thunderstorms are expected in 60% of the area, with heavy rain in some places, especially in Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat.
• Minimum temperature: 23-25°C
• Maximum temperature: 33-36°C
• South-westerly winds: 15-30 km/h
• Waves about one metre high, and above two metres in thunderstorm areas.

South (West Coast)

• Thunderstorms are expected in 60% of the area, with heavy rain in some places, especially in Phuket, Krabi, Trang and Satun.
• Minimum temperature: 23-26°C
• Maximum temperature: 32-35°C
• From Phuket northwards: south-westerly winds of 15-35 km/h. Waves 1-2 metres high, and above two metres in thunderstorm areas.
• From Krabi southwards: south-westerly winds of 15-30 km/h. Waves about one metre high, and above two metres in thunderstorm areas.

Bangkok and surrounding provinces

• Thunderstorms are expected in 70% of the area, with heavy rain in some places.
• Minimum temperature: 24-26°C
• Maximum temperature: 34-36°C
• South-westerly winds: 10-20 km/h.