Flooding possible in Thailand's East and South amid intense rain

The Thai Meteorological Department (TMD) stated in the forecast for Sunday (September 13, 2026) that “parts of the East and South will experience heavy to very heavy rain”, while isolated heavy rain was also forecast in the Northeast, Central region, Bangkok and surrounding provinces.

Residents in those areas were warned that heavy to very heavy rain and accumulated rainfall could cause flash floods, forest run-off and landslides, particularly on foothill slopes near waterways and in low-lying areas.

Travel on routes repeatedly affected by flooding should be avoided, especially in low-lying areas where temporary flooding may occur.

The conditions are being caused by a high-pressure system or cool air mass extending across the upper North and upper Northeast, while a monsoon trough lies across the lower Central region, upper South, upper Gulf of Thailand and East, extending into an active low-pressure cell over the coast of central Vietnam.

A moderate southwest monsoon is prevailing over the Andaman Sea, the South and the Gulf of Thailand.

Wind and wave conditions in the Andaman Sea and the Gulf of Thailand are moderate.

In the upper Andaman Sea, waves are about 2 metres high and more than 2 metres in thunderstorm areas.

Mariners in the Andaman Sea and the Gulf of Thailand are advised to proceed with caution and avoid areas experiencing thunderstorms.

Northern region

• Thunderstorms are forecast across 40% of the region, mainly in Phitsanulok, Phichit and Phetchabun provinces.
• Minimum temperature: 21–26°C
• Maximum temperature: 33–37°C
• Easterly winds: 10–20 kilometres per hour

Northeastern region

• Thunderstorms are forecast across 60% of the region, with isolated heavy rain in Nakhon Phanom, Sakon Nakhon, Mukdahan, Yasothon, Kalasin, Khon Kaen, Chaiyaphum, Nakhon Ratchasima, Maha Sarakham, Roi Et, Amnat Charoen, Surin, Si Sa Ket and Ubon Ratchathani provinces.
• Minimum temperature: 21–25°C
• Maximum temperature: 30–33°C
• Northeasterly winds: 10–20 kilometres per hour

Central region

• Thunderstorms are forecast across 70% of the region, with isolated heavy rain in Lop Buri, Saraburi, Kanchanaburi, Ratchaburi, Samut Songkhram and Samut Sakhon provinces.
• Minimum temperature: 22–25°C
• Maximum temperature: 34–36°C
• Variable winds: 10–20 kilometres per hour

Eastern region

• Thunderstorms are forecast across 70% of the region, with isolated heavy rain in Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chon Buri and Rayong provinces. Isolated very heavy rain is forecast in Chanthaburi and Trat provinces.
• Minimum temperature: 23–26°C
• Maximum temperature: 31–34°C
• Variable winds: 15–35 kilometres per hour
• Waves: 1–2 metres, rising above 2 metres in thunderstorm areas

Southern region, east coast

• Thunderstorms are forecast across 70% of the region, with isolated heavy rain in Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Songkhla and Yala provinces.
• Minimum temperature: 22–24°C
• Maximum temperature: 29–33°C
• From Surat Thani northwards: Westerly winds of 15–35 kilometres per hour, with waves of 1–2 metres and above 2 metres in thunderstorm areas
• From Nakhon Si Thammarat southwards: Northwesterly winds of 15–35 kilometres per hour, with waves of about 1 metre, rising to 1–2 metres offshore and above 2 metres in thunderstorm areas

Southern region, west coast

• Thunderstorms are forecast across 80% of the region, with isolated heavy rain in Phuket, Krabi, Trang and Satun provinces. Isolated very heavy rain is forecast in Ranong and Phang Nga provinces.
• Minimum temperature: 23–25°C
• Maximum temperature: 29–32°C
• From Phuket northwards: Westerly winds of 20–35 kilometres per hour, with waves of about 2 metres and above 2 metres in thunderstorm areas
• From Krabi southwards: Northwesterly winds of 15–35 kilometres per hour, with waves of 1–2 metres and above 2 metres in thunderstorm areas

Bangkok and surrounding provinces

• Thunderstorms are forecast across 70% of the area, with isolated heavy rain.
• Minimum temperature: 24–26°C
• Maximum temperature: 33–34°C
• Variable winds: 10–20 kilometres per hour