Phuket and Andaman Sea forecast: 17–22 August 2025
This Phuket and Andaman Sea forecast covers the six days from Sunday 17 August to Friday 22 August 2025, with daily temperatures, rainfall coverage, sailing conditions and tide notes for the Andaman Sea region of Thailand. It is aimed at travellers planning island crossings during Thailand's southwest monsoon, when sea state matters more than sunshine.
Weather Forecast for the Andaman Sea Region, Thailand. 17 August to 22 August, 2025.
- Sunday, August 17 — Temperature: 33–26°C. Weather: Heavy rain, 60% of area. Sailing Conditions: Moderate, waves 1.5–2 m. Tide: Low tide midday, rising in evening.
- Monday, August 18 — Temperature: 34–26°C. Weather: Heavy rain, 40% of area. Sailing Conditions: Moderate to rough, waves 1.8–2 m. Tide: High tide early morning, low tide afternoon.
- Tuesday, August 19 — Temperature: 34–26°C. Weather: Heavy rain, 40% of area. Sailing Conditions: Moderate, waves ~2 m. Tide: Low tide morning, rising later.
- Wednesday, August 20 — Temperature: 34–27°C. Weather: Heavy rain, 40% of area. Sailing Conditions: Moderate, waves 1.5–2 m. Tide: Rising afternoon.
- Thursday, August 21 — Temperature: 33–26°C. Weather: Heavy rain, 40% of area. Sailing Conditions: Moderate, waves 1.5–2 m. Tide: High tide early afternoon.
- Friday, August 22 — Temperature: 33–26°C. Weather: Heavy rain, 40% of area. Sailing Conditions: Moderate to rough, waves up to 2 m. Tide: Lowering in evening.
What changed this week
The wettest day of the period is Sunday 17 August, with heavy rain across 60% of the area. From Monday onwards rainfall coverage settles at 40% of the area, while daytime highs edge up to 34°C on Monday, Tuesday and Wednesday before easing back to 33°C. Overnight lows hold steady at 26–27°C throughout.
Sea state is the detail worth watching. Conditions are moderate on most days with waves of 1.5–2 m, but turn moderate to rough on Monday 18 August (1.8–2 m) and again on Friday 22 August, with waves up to 2 m.
Who this affects
Anyone crossing open water in the Andaman Sea is affected, including passengers on ferry and speedboat services between Phuket and the surrounding islands. Speedboats and smaller craft feel 2 m swell far more than larger vessels, so the moderate-to-rough days are the ones most likely to bring a bumpy ride. Road-based services such as buses, minivans and private transfers are less exposed to swell, though heavy rain can still slow journeys.
Practical tips for travellers
- Book early departures where possible — seas and rainfall often build through the day.
- Allow buffer time before onward flights or connections rather than booking tight transfers.
- Tides shift daily this week, so check your operator's confirmed departure time rather than assuming a fixed timetable.
- Pack a dry bag for luggage and bring motion-sickness remedies for the rougher days.
- Consider a road transfer as a backup if you are prone to seasickness.
Check your route
Departure times, operators and vessel types vary by route, and services can be adjusted or cancelled at short notice in rough conditions. Search your specific journey to see live availability, current timetables and up-to-date prices, and read the operator's booking conditions before you pay.
Disclaimer: Weather, sea conditions, and tide information are subject to change. Always check local updates and forecasts before planning activities.
Planning a crossing this week? Search availability for your Andaman Sea route and book with confidence.
