The Meteorological Department issued its third announcement warning of very heavy rain from 18–20 Oct, focusing on the South and East regions, before increasing across many areas including Bangkok from 21–25 Oct. Risk areas are advised to monitor for flash floods and sudden mountain runoff caused by heavy rains.
On 18 Oct 2026, the Meteorological Department's Facebook page posted its third announcement at 05:00, updating areas forecasted for heavy to very heavy rain, dividing the overall outlook into two key periods.
18–20 Oct | Rain focused on the South and East regions.
21–25 Oct | Increased rain in many areas.
What changes from the second announcement?
On 21 Oct, areas forecasted for very heavy rain were reduced to only Chonburi, down from the earlier forecast including Chonburi, Rayong, Chanthaburi, and Phetchaburi.
On 22 Oct, no areas are forecasted for very heavy rain in the latest table, though some heavy rain remains expected in the Central, East, and South regions.
On 24 Oct, very heavy rain continues to focus on Phang Nga, Phuket, and Krabi.
On 25 Oct, areas forecasted for very heavy rain adjusted to Phang Nga, Phuket, and Krabi, down from the previous list of Phetchaburi, Prachuap Khiri Khan, Ranong, Phang Nga, and Phuket.
Bangkok and its vicinity.
Still forecasted for some heavy rain during 21–23 Oct.
What precautions are needed for this rain?
Boat operators in the Gulf of Thailand and Andaman Sea.
In areas with thunderstorms and waves over 3 meters high, navigate with caution and avoid stormy zones.
Forecasted areas are predictions and do not guarantee heavy rain at every point or time; adjustments do not mean removed areas will have no rain.
Meteorological Department — Monitor weather forecasts, warnings, and rain radar closely.
Royal Irrigation Department / National Water Resources Office — Track water levels and situations.
Department of Disaster Prevention and Mitigation / Provincial / Local authorities — Follow warnings and risk area information.
Next announcement on 18 Oct 2026 at 17:00. Please stay updated as forecasts may change.
For the full announcement content regardingHeavy to Very Heavy Rain in Thailand, Announcement No. 3,it states that from 18–20 Oct 2026, continuous rain with heavy to very heavy rainfall will focus on the South and East. From 21–25 Oct, increased rain and heavy to very heavy rain with gusty winds will occur in the lower Northeast, Central region, including Bangkok and vicinity, East, and upper South.
Residents in these areas should be cautious of hazards from strong gusty winds, heavy to very heavy rain, and continuous rainfall accumulation, which may cause flash floods, mountain runoff, and landslides, especially near foothills and waterways and in low-lying areas. Avoid traveling through flood-prone routes, especially lowlands prone to short-term waterlogging.
This situation arises as a monsoon trough passes over the lower South, combined with the southwest monsoon covering the lower Andaman Sea. Then the monsoon trough shifts to the central South, while high-pressure or cold air masses from China cover upper North, upper Northeast, and the South China Sea.
In the Andaman Sea and Gulf of Thailand, thunderstorms will produce waves over 3 meters high. Boat operators in these seas should navigate carefully and avoid areas with thunderstorms.
For safety and to reduce possible impacts, the public should plan their activities and travel carefully during this period and keep up to date with announcements from the Meteorological Department via their website.http://www.tmd.go.thOr call 0-2399-4012-13 and 1182, available 24 hours.
Information from the Meteorological Department.