Monsoon brings widespread rain; Bangkok faces 70% storm risk

The Thai Meteorological Department (TMD) has warned of intense rainfall in several regions, with a 70% chance of thunderstorms forecast for Bangkok and surrounding provinces.

The 24-hour forecast indicates that northern, northeastern, eastern and southern provinces will experience heavy rain in some areas. 

Residents in these regions are advised to be cautious of potential flash floods and runoff, particularly in foothills, near waterways, and low-lying areas.

The unsettled weather is being driven by a low-pressure system covering upper Myanmar and northern Laos, in combination with a moderate southwest monsoon currently sweeping over the Andaman Sea, Thailand, and the Gulf of Thailand.

Rough seas warning for Andaman and Gulf of Thailand

Marine conditions are expected to remain moderately rough, with waves in the upper Andaman Sea reaching about 2 metres. 

The lower Andaman Sea and the upper Gulf of Thailand can expect waves between 1-2 metres, with waves potentially exceeding 2 metres in thunderstorm zones. 

Mariners are advised to proceed with caution and avoid sailing in areas experiencing thunderstorms.

Tropical Storm Danas intensifies near Taiwan, but no direct impact on Thailand

Meanwhile, Tropical Storm “Danas” in the upper South China Sea is forecast to approach Taiwan between July 6–7. 

Although it is not expected to make landfall in Thailand, it will enhance the strength of the southwest monsoon over the country, potentially prolonging the current period of heavy rainfall.

Regional Forecast Highlights (Valid from 6am Sunday, July 6  to 6am Monday, July 7)

Bangkok and vicinity:

Thunderstorms cover 70% of the area

• Minimum temperature: 26–27°C
• Maximum temperature: 33–35°C
• Southwesterly winds at 10–20 km/h

Northern Region:

Thunderstorms cover 80% of the area with heavy rain in some places, particularly in Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Nan, Phrae, Uttaradit, Tak, Phitsanulok, and Phetchabun

• Minimum temperature: 23–26°C
• Maximum temperature: 30–34°C
• Southwesterly winds at 10–20 km/h

Northeastern Region:

Thunderstorms cover 70% of the area with heavy rain in some provinces, including Loei, Nong Khai, Bueng Kan, Nong Bua Lamphu, Udon Thani, Sakon Nakhon, Nakhon Phanom, Mukdahan, Kalasin, Roi Et, Yasothon, Amnat Charoen, Si Sa Ket, and Ubon Ratchathani

• Minimum temperature: 23–26°C
• Maximum temperature: 32–35°C
• Southwesterly winds at 10–20 km/h

Central Region:

Thunderstorms are expected over 70% of the area, particularly in Nakhon Sawan, Uthai Thani, Kanchanaburi, Nakhon Pathom, Ratchaburi, Samut Songkhram, and Samut Sakhon.

• Minimum temperature: 24–27°C
• Maximum temperature: 33–36°C
• Southwesterly winds at 10–20 km/h

Eastern Region:

Thunderstorms are expected across 70% of the region, with heavy rain in some areas, including Nakhon Nayok, Prachin Buri, Chanthaburi, and Trat.

• Minimum temperature: 25–28°C
• Maximum temperature: 32–34°C
• Southwesterly winds at 15–35 km/h
• Offshore waves reaching 1–2 metres; over 2 metres in thunderstorm zones

Southern Region (east coast):

Scattered thunderstorms (40% of the area), mostly affecting Phetchaburi, Prachuap Khiri Khan, Chumphon, and Surat Thani.

• Minimum temperature: 23–25°C
• Maximum temperature: 33–35°C
• Southwesterly winds at 15–35 km/h
• Waves around 1 metre near shore, 1–2 metres further out, exceeding 2 metres during thunderstorms

Southern Region (west coast):

Thunderstorms over 60% of the area, with heavy rain likely in Ranong and Phang Nga.

• Minimum temperature: 24–27°C
• Maximum temperature: 32–34°C
• From Phang Nga northwards: Southwesterly winds at 20–35 km/h, waves up to 2 metres; higher in stormy areas
• From Phuket southwards: Southwesterly winds at 15–35 km/h, waves 1–2 metres; exceeding 2 metres in thunderstorm zones