TMD Forecasts rain and thunderstorms in 31 provinces on August 20

The Thai Meteorological Department (TMD) has issued a weather forecast for August 20, 2025, warning 31 provinces to prepare for rain and thunderstorms due to the influence of a weakening southwest monsoon covering the Andaman Sea.

The forecast for the next 24 hours indicates reduced rainfall in Thailand, although thunderstorms will persist in some areas, primarily due to the weakening southwest monsoon affecting the Andaman Sea and the Gulf of Thailand. Additionally, a low-pressure system is present over northern Vietnam.

In the Andaman Sea, moderate winds are expected, with wave heights reaching 1-2 metres in the upper part of the sea, while the lower part of the Andaman Sea and the Gulf of Thailand will see waves up to 1 metre. Areas experiencing thunderstorms may see waves exceeding 2 metres. Mariners are advised to exercise caution and avoid sailing in stormy areas.

Thailand Weather Forecast by the Meteorological Department: 6am on Wednesday (August 20) to 6am on Thursday (August 21)

Thailand Weather Forecast by the Meteorological Department: 6am on Wednesday (August 20) to 6am on Thursday (August 21)

Bangkok and Vicinity

Thunderstorms are expected in 30% of the area.

Minimum temperature: 25-26°C

Maximum temperature: 33-36°C

Southwest winds at 10-15 km/h

Northern Thailand

Thunderstorms in 20% of the area, mainly in Mae Hong Son, Chiang Mai, Tak, Kamphaeng Phet, and Phetchabun.

Minimum temperature: 23-25°C

Maximum temperature: 33-36°C

Southwest winds at 5-15 km/h

Northeastern Thailand

Thunderstorms in 40% of the area, primarily in Bung Kan, Sakon Nakhon, Nakhon Phanom, Nakhon Ratchasima, Buri Ram, and Surin.

Minimum temperature: 23-25°C

Maximum temperature: 33-34°C

Southwest winds at 10-15 km/h

Central Thailand

Thunderstorms in 30% of the area, especially in Kanchanaburi, Suphan Buri, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon.

Minimum temperature: 23-25°C

Maximum temperature: 34-36°C

Southwest winds at 10-15 km/h

Eastern Thailand

Thunderstorms in 30% of the area, mainly in Nakhon Nayok, Chonburi, and Trat.

Minimum temperature: 23-25°C

Maximum temperature: 32-34°C

Southwest winds at 15-30 km/h

Waves in the sea are approximately 1 metre high, with higher waves of over 2 metres in stormy areas

Southern Thailand (Eastern Coast)

Thunderstorms are expected in 30% of the area, particularly in Phetchaburi, Prachuap Khiri Khan, Songkhla, Pattani, Yala, and Narathiwat.

Minimum temperature: 23-26°C

Maximum temperature: 33-35°C

Southwest winds at 15-30 km/h

Waves in the sea are about 1 metre high, with higher waves of over 2 metres in stormy areas

Southern Thailand (Western Coast)

Thunderstorms in 20% of the area, mainly in Ranong and Phang Nga.

Minimum temperature: 24-26°C

Maximum temperature: 33-34°C

From Phuket upwards: Southwest winds at 15-35 km/h, waves 1-2 metres high, with higher waves in stormy areas

From Krabi downwards: Southwest winds at 15-30 km/h, waves about 1 metre high, with waves of 1-2 metres in stormy areas

(2025/08/20-00:00)