Weather and tide forecast for the Gulf of Thailand (Samui, Phangan, Tao and Surat Thani)
This weather and tide forecast for the Gulf of Thailand covers Koh Samui, Koh Phangan, Koh Tao and the mainland gateway of Surat Thani, so you can see at a glance how comfortable a crossing is likely to be before you book. Below is the published outlook for the forecast week, followed by what the numbers mean in practice.
Weather Forecast for Gulf of Thailand (Samui/Phangan/Tao/Surat Thani) Jan 20, 2025 – January 26, 2025
- Monday, Jan 20 — Temperature: 30°C (86°F) High, 24°C (76°F) Low. Weather: Mostly sunny. Sailing Conditions: Moderate (Wave height: 0.8-1m). Tide: High at 2:20 PM (1.91m), Low at 9:43 PM (0.94m)
- Tuesday, Jan 21 — Temperature: 29°C (85°F) High, 25°C (77°F) Low. Weather: Partly cloudy. Sailing Conditions: Moderate (Wave height: 0.7-0.9m). Tide: High at 3:04 PM (1.87m), Low at 10:23 PM (1.02m)
- Wednesday, Jan 22 — Temperature: 30°C (86°F) High, 26°C (78°F) Low. Weather: Cloudy. Sailing Conditions: Slightly rough (Wave height: 1-1.2m). Tide: High at 3:50 PM (1.81m), Low at 11:05 PM (1.12m)
- Thursday, Jan 23 — Temperature: 30°C (86°F) High, 25°C (77°F) Low. Weather: Mostly cloudy. Sailing Conditions: Moderate (Wave height: 0.8-1m). Tide: High at 4:37 PM (1.74m), Low at 11:48 PM (1.23m)
- Friday, Jan 24 — Temperature: 30°C (86°F) High, 26°C (79°F) Low. Weather: Partly sunny. Sailing Conditions: Calm (Wave height: 0.7-0.9m). Tide: High at 5:26 PM (1.66m)
- Saturday, Jan 25 — Temperature: 30°C (85°F) High, 27°C (80°F) Low. Weather: Rain in the morning. Sailing Conditions: Moderate (Wave height: 1-1.3m). Tide: Low at 12:32 AM (1.34m), High at 6:16 PM (1.57m)
- Sunday, Jan 26 — Temperature: 29°C (85°F) High, 28°C (83°F) Low. Weather: Cloudy with rain. Sailing Conditions: Slightly rough (Wave height: 1.2-1.5m). Tide: Low at 1:18 AM (1.46m), High at 7:07 PM (1.46m)
What changed across the week
The week opens bright and settles into cloud. Monday is the warmest, driest start, Friday is the single calmest day for sailing, and conditions then turn: rain arrives on Saturday morning and Sunday is both the wettest and the roughest day, with the highest wave range of the week at 1.2–1.5m.
Temperatures barely move — highs sit at 29–30°C throughout — so the practical difference between days is sea state and rain, not heat. Overnight lows climb steadily from 24°C on Monday to 28°C on Sunday, which usually signals more humid, unsettled air.
How sailing conditions affect your crossing
Wave height is the number to watch if you are prone to seasickness. Days marked Calm or Moderate (roughly 0.7–1m here) are comfortable for most passengers. Slightly rough days — Wednesday and Sunday — can mean noticeable motion on faster, lighter craft, and operators may adjust or cancel departures if conditions deteriorate.
Booking around the rougher days
If your dates are flexible, the mid-week and Friday windows read best. If you must travel Saturday or Sunday, consider an earlier departure, sit low and central on board, and allow buffer time before onward flights or connections.
Reading the tide times
Tidal range in this part of the Gulf is modest — highs between 1.46m and 1.91m across the week — but low water can still affect shallow piers, beach landings, longtail transfers and swimming conditions. Note that high tide shifts later each day, from 2:20 PM on Monday to 7:07 PM on Sunday.
Routes and services this affects
These conditions apply to island-hopping and mainland crossings alike. Check timings and availability for Surat Thani to Koh Samui, Koh Samui to Koh Phangan and Koh Phangan to Koh Tao, or browse our Koh Tao destination guide for arrival details.
Where a route is sold as a combined ticket — bus, minivan or private transfer paired with a sea crossing — a delayed or cancelled sailing can affect the land leg too. Your booking confirmation and the operator's own conditions are the authority on rebooking and refunds.
Data notes
Please flag for review: the forecast above is dated 20–26 January 2025 and is not live data. Actual departure times, operators, durations and fares are not included on this page — always confirm those on the route page at the time of booking.
Disclaimer: Weather, sea conditions, and tide information are subject to change. Always check local updates and forecasts before planning activities.
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