Photo: Andre Mouton / Pexels
Heavy rain is forecast in 33 provinces across Thailand on 11 October 2026, down from 46 on 10 October and 16 on 9 October. The Central, East and South regions are worst hit, and five provinces face very heavy rain. Koh Lanta falls under the South (west coast) forecast: scattered thundershowers, isolated heavy rain, highs of 32-34°C and waves of 1-2 m that can top 2 m in storms. Boat trips and ferries may be affected.
The big picture
The Thai Meteorological Department says heavy rain is expected in 33 provinces today. The worst-hit areas are the Central, East and South regions. Very heavy rain is forecast for Kanchanaburi, Ratchaburi, Samut Songkhram, Phetchaburi and Prachuap Khiri Khan.
The department also warns of flash floods and overflows along waterways near foothills and lowlands.
What is driving the weather
- A high pressure system from China covers the upper North and the upper Northeast.
- Easterly and southeasterly winds are carrying moisture from the South China Sea to the eastern Northeast and the East.
- A monsoon trough lies across the Gulf and the South.
- Rain should ease afterward in the upper North and upper Northeast.
Koh Lanta and the Andaman coast
Koh Lanta sits under the "South, west coast (Andaman)" forecast. Expect:
- Scattered thundershowers with isolated heavy rain
- Lows of 23-25°C and highs of 32-34°C
- North-westerly winds of 15-30 km/h
- Waves of 1-2 m, rising above 2 m in thundershowers
Rough seas could affect ferry and speedboat operations, and island trips may be bumpy or cancelled. If you have a boat day planned, check with your operator before you head out. The same forecast covers Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
Forecast by region
| Region | Conditions | Low | High | Wind |
|---|---|---|---|---|
| Bangkok | Fairly widespread thundershowers, gusty wind, isolated heavy rain | 25-27°C | 32-34°C | NE 10-20 km/h |
| North | Scattered thundershowers, isolated heavy rain (Tak, Kamphaeng Phet) | 20-25°C | 32-36°C | E 10-20 km/h |
| Northeast | Isolated thundershowers (Khon Kaen, Chaiyaphum, Nakhon Ratchasima, Buri Ram) | 22-24°C | 31-34°C | NE 10-25 km/h |
| Central | Widespread thundershowers, isolated heavy rain (Nakhon Sawan, Uthai Thani, Chai Nat, Ayutthaya, Suphan Buri, Nakhon Pathom, Samut Sakhon); isolated very heavy rain (Kanchanaburi, Ratchaburi, Samut Songkhram) | 23-26°C | 33-35°C | E 10-20 km/h |
| East | Widespread thundershowers, isolated heavy rain (Nakhon Nayok, Chachoengsao, Chon Buri, Rayong, Chanthaburi, Trat) | 23-27°C | 31-34°C | E 15-30 km/h |
| South, east coast | Widespread thundershowers, isolated heavy rain (Chumphon, Surat Thani, Nakhon Si Thammarat, Pattani, Phatthalung, Songkhla, Yala, Narathiwat); isolated very heavy rain (Phetchaburi, Prachuap Khiri Khan) | 22-25°C | 31-34°C | Variable 15-30 km/h |
| South, west coast (Andaman) | Scattered thundershowers, isolated heavy rain (Ranong, Phang Nga, Phuket, Krabi, Trang, Satun) | 23-25°C | 32-34°C | NW 15-30 km/h |
Sea conditions
Waves are 1-2 m in both east and west coast waters, and above 2 m where thundershowers hit. In the Andaman Sea and the Gulf, waves exceed 2 m in thundershower areas. Ships should avoid thundershowers.
Tips for travellers
- Bring rain gear wherever you go. Thundershowers are likely across nearly the whole country, with the heaviest rain in the Central region, the East and the South.
- Gulf-side islands and the east coast face a more widespread rain risk than the Andaman side.
- Stay away from streams and waterfalls in foothills and lowlands, where flash floods can happen.
- If you are passing through Bangkok, expect travel delays from heavy downpours and gusty wind.
- The North and Northeast are drier, and rain is set to ease there.
Information sourced from The Thaiger.