Bangkok and Northeast face heavy rain as flood risk rises nationwide
Bangkok and nearby provinces face thunderstorms across 60% of the area, while heavy rain raises flash-flood and run-off risks.
- Bangkok and its surrounding provinces are forecast to have thunderstorms across 60% of the area, with heavy rain expected in the capital.
- The Northeast region is also expected to face strong winds and thunderstorms, which could trigger flash floods and run-off.
- A nationwide warning has been issued for the public to be aware of potential flash floods and run-off from heavy rain, particularly in low-lying and foothill areas.
- The severe weather is caused by a strong southwest monsoon, which is also bringing heavy rain to other parts of Thailand, including the South's west coast and the East.
The Thai Meteorological Department’s forecast for Monday (May 18, 2026) warns Bangkok and surrounding provinces of thunderstorms across 60% of the area, with heavy rain expected across the capital.
The Northeast is also expected to face strong winds and thunderstorms that could trigger flash floods and run-off.
Over the next 24 hours, upper Thailand is forecast to see isolated heavy rain, mainly in the west of the country and the upper Northeast.
Heavy to very heavy rain is also forecast in parts of the South’s west coast and the East, as the rather strong south-west monsoon prevails over the upper Andaman Sea and Thailand.
People are advised to beware of heavy to very heavy rain and accumulated rainfall, which could cause flash floods and run-off, especially on foothill slopes near waterways and in low-lying areas.
They are also advised to take care of their health during changing weather conditions.
Sea conditions in the upper Andaman Sea are rather strong, with waves 2–3 metres high and above 3 metres in thunderstorm areas.
The lower Andaman Sea and the upper Gulf of Thailand will see waves 1–2 metres high and above 2 metres in thunderstorm areas.
Mariners in these areas should navigate with caution and avoid sailing in thunderstorms, while small boats in the upper Andaman Sea should remain ashore.
Weather forecast for Thailand from 6am on Monday (May 18, 2026) to 6am on Tuesday (May 19, 2026)
Bangkok and vicinity
- Thunderstorms are forecast in 60% of the area.
- Minimum temperature: 26–28 degrees Celsius
- Maximum temperature: 34–36 degrees Celsius
- South-westerly winds: 10–20km/h
North
- Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Tak, Kamphaeng Phet, Phichit, Phitsanulok and Phetchabun.
- Minimum temperature: 22–26 degrees Celsius
- Maximum temperature: 35–38 degrees Celsius
- South-westerly winds: 10–20km/h
Northeast
- Thunderstorms are forecast in 70% of the area, with isolated heavy rain in Loei, Nong Khai, Bueng Kan, Nong Bua Lam Phu, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Khon Kaen, Kalasin, Mukdahan, Yasothon, Amnat Charoen, Nakhon Ratchasima, Si Sa Ket and Ubon Ratchathani.
- Minimum temperature: 24–26 degrees Celsius
- Maximum temperature: 32–35 degrees Celsius
- South-westerly winds: 10–20km/h
Central region
- Thunderstorms are forecast in 70% of the area, with isolated heavy rain in Nakhon Sawan, Uthai Thani, Chai Nat, Sing Buri, Ang Thong, Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi and Ratchaburi.
- Minimum temperature: 25–26 degrees Celsius
- Maximum temperature: 35–37 degrees Celsius
- South-westerly winds: 10–20km/h
East
- Thunderstorms are forecast in 60% of the area, with isolated heavy to very heavy rain in Nakhon Nayok, Prachin Buri, Chachoengsao, Chon Buri, Rayong, Chanthaburi and Trat.
- Minimum temperature: 25–27 degrees Celsius
- Maximum temperature: 32–35 degrees Celsius
- South-westerly winds: 15–35km/h
- Waves will be 1–2 metres high and above 2 metres in thunderstorm areas.
South, east coast
- Thunderstorms are forecast in 60% of the area, with isolated heavy rain in Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung and Songkhla.
- Minimum temperature: 23–26 degrees Celsius
- Maximum temperature: 34–36 degrees Celsius
- South-westerly winds: 15–35km/h
- Waves will be about 1 metre high, rising to 1–2 metres offshore and above 2 metres in thunderstorm areas.
South, west coast
- Thunderstorms are forecast in 70% of the area, with isolated heavy to very heavy rain in Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
- Minimum temperature: 22–24 degrees Celsius
- Maximum temperature: 31–33 degrees Celsius
- From Phuket northwards: south-westerly winds of 20–40km/h, with waves 2–3 metres high and above 3 metres in thunderstorm areas.
- From Krabi southwards: south-westerly winds of 15–35km/h, with waves 1–2 metres high and above 2 metres in thunderstorm areas.
