Thailand Issues Heavy Rain Warning Through October 13

Thailand’s Meteorological Department has issued its ninth warning for a period of unsettled weather expected to bring heavy and very heavy rain, thunderstorms, strong wind gusts, hail and lightning between October 11 and 13. The alert covers several regions, including Bangkok and Chonburi, with the affected area expected to narrow to the South on October 12 and 13.

Warning No. 9 (255/2026) took effect at 5am on October 11. It was signed by Deputy Director-General Nattawut Dande, who was serving as acting director-general. The next update was scheduled for 5pm the same day.

On October 11, the warning covered the lower North, the Central region—including Bangkok and its surrounding areas—the East and the South. For the following two days, the alert was expected to focus on the South.

The department attributed the weather conditions to a high-pressure system from China affecting upper Thailand, easterly and southeasterly winds over the Northeast, East and Gulf of Thailand, and the southwest monsoon over the Andaman Sea, together with a monsoon trough over the upper South.

Authorities urged residents to remain alert for accumulated rainfall that could trigger flash floods, overflowing waterways and landslides, particularly along waterways near foothills and in low-lying areas. During storms, people were advised to stay away from open areas, large trees and unsecured billboards because of the risk of lightning and strong winds.

Eastern Thailand faces widespread thunderstorms

The forecast for Sunday, October 11, indicated thunderstorms across around 70% of the eastern region, with isolated strong winds and heavy rain expected in Nakhon Nayok, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat. Overnight forecasts also indicated a particularly high risk of thunderstorms in Rayong, Chanthaburi and Trat.

Temperatures in the East were forecast to range from 23–27°C at night to 31–34°C during the day. Easterly winds were expected at 15–30 kilometres per hour. Sea conditions were forecast to produce waves of around one metre, rising above two metres during thunderstorms.

The department warned vessels operating in the Gulf of Thailand and the Andaman Sea to exercise caution, as waves could exceed two metres during storms. Boats were advised to avoid areas experiencing thunderstorms.

Pattaya on alert for flooding and rough seas

Pattaya lies within the eastern region covered by the warning. On October 9, Mayor Poramese Ngampichet ordered round-the-clock monitoring of flood risks and rough sea conditions after the same weather system was forecast to affect Chonburi.

Heavy rain in late September had already flooded the Bang Lamung Canal area, affecting more than 250 homes. At the time, the city’s drainage system was reported to be capable of handling approximately 60–70 millimetres of rainfall per day before water began accumulating on roads.

The latest warning does not state that Pattaya will necessarily experience flooding. However, the forecast conditions increase the risk of flash floods and water accumulation, making continued monitoring and caution important.