Southwest monsoon brings more rain and thunderstorms across Thailand
Heavy rain is forecast in parts of upper Thailand, with mariners advised to avoid thundery areas where waves may exceed 2 metres.
- A moderate southwest monsoon is causing increased rain and thunderstorms across Thailand, with isolated heavy downpours expected in the North, Northeast, Central, and Eastern regions.
- The northern region is forecast to experience the highest rain coverage at 70%, while Bangkok and surrounding provinces are predicted to have thunderstorms across 60% of the area.
- Authorities have warned residents in upper Thailand about heavy rain and advised mariners to be cautious of waves reaching 1-2 meters, and over 2 meters in thundery areas.
The Thai Meteorological Department (TMD) forecast more rain across Thailand on Thursday (July 23, 2026), as the southwest monsoon affected the country.
The North was expected to have the highest rain coverage, at 70% of the region, while Bangkok and surrounding provinces were forecast to see thunderstorms and strong winds.
Over the next 24 hours, isolated heavy rain was forecast in the North, Northeast, Central region, including Bangkok and surrounding provinces, and the East.
The conditions were attributed to a moderate southwest monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand, together with a low-pressure area over upper Vietnam.
People in upper Thailand were advised to beware of heavy and accumulated rain.
The upper Andaman Sea and upper Gulf of Thailand were expected to have waves 1–2 metres high, while waves in the lower Andaman Sea would be about 1 metre.
Waves could exceed 2 metres in thundery areas.
Mariners were advised to proceed with caution and avoid sailing in areas with thunderstorms.
An active low-pressure area over the Pacific Ocean was expected to intensify into a tropical depression and move across the northern Philippines from Friday to Saturday (July 24–25).
Thailand forecast from 6am on Thursday (July 23) to 6am on Friday (July 24)
Bangkok and surrounding provinces
- Thunderstorms are forecast across 60% of the area, with isolated heavy rain.
- Minimum temperature: 26–27°C
- Maximum temperature: 34–36°C
- Southwesterly winds: 10–20 km/h
North
- Thunderstorms are forecast across 70% of the area, with isolated heavy rain in Mae Hong Son, Chiang Mai, Phrae, Nan, Uttaradit, Tak, Sukhothai, Phitsanulok and Phetchabun.
- Minimum temperature: 22–26°C
- Maximum temperature: 29–34°C
- Southwesterly winds: 10–20 km/h
Northeast
- Thunderstorms are forecast across 60% of the area, with isolated heavy rain in Udon Thani, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Khon Kaen, Maha Sarakham, Amnat Charoen and Ubon Ratchathani.
- Minimum temperature: 23–25°C
- Maximum temperature: 29–35°C
- Southwesterly winds: 10–20 km/h
Central region
- Thunderstorms are forecast across 60% of the area, with isolated heavy rain in Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Kanchanaburi and Ratchaburi.
- Minimum temperature: 24–26°C
- Maximum temperature: 33–36°C
- Southwesterly winds: 10–20 km/h
East
- Thunderstorms are forecast across 60% of the area, with isolated heavy rain in Nakhon Nayok, Chonburi, Rayong, Chanthaburi and Trat.
- Minimum temperature: 24–28°C
- Maximum temperature: 33–35°C
- Southwesterly winds: 15–35 km/h
- Wave height: 1–2 metres, rising above 2 metres in thundery areas
South (east coast)
- Thunderstorms are forecast across 30% of the area, mainly in Phetchaburi, Prachuap Khiri Khan, Chumphon, Pattani and Yala.
- Minimum temperature: 24–26°C
- Maximum temperature: 34–36°C
- Southwesterly winds: 15–30 km/h
- Wave height: about 1 metre, rising above 1 metre offshore and above 2 metres in thundery areas
South (west coast)
- Thunderstorms are forecast across 40% of the area, mainly in Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
- Minimum temperature: 24–27°C
- Maximum temperature: 32–35°C
- From Phang Nga northwards, southwesterly winds are forecast at 15–35 km/h, with waves 1–2 metres high and above 2 metres in thundery areas.
- From Phuket southwards, southwesterly winds are forecast at 15–30 km/h, with waves about 1 metre high and above 2 metres in thundery areas.
