Weather and tide forecast for the Gulf of Thailand (Samui/Phangan/Tao/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 how sea conditions are likely to affect your crossing before you travel.
Each day below lists daytime and night-time temperatures, the general weather picture, expected sailing conditions with wave heights, and the main high and low tide times.
Weather Forecast for Gulf of Thailand (Samui/Phangan/Tao/Surat Thani) December 9–15, 2024
Monday, Dec 9
- Temperature: 85°F (29°C) / 78°F (26°C)
- Weather: Rainy
- Sailing Conditions: Moderate; Waves 1.5–2m
- Tide: High at 3:46 PM (2.08m), Low at 1:42 AM (0.92m)
Tuesday, Dec 10
- Temperature: 87°F (31°C) / 79°F (26°C)
- Weather: Cloudy, occasional showers
- Sailing Conditions: Moderate; Waves 1.5–2m
- Tide: High at 4:13 PM (1.80m), Low at 1:15 AM (1.06m)
Wednesday, Dec 11
- Temperature: 88°F (31°C) / 79°F (26°C)
- Weather: Partly sunny
- Sailing Conditions: Calm; Waves 1–1.5m
- Tide: High at 8:26 AM (1.65m), Low at 12:04 AM (1.14m)
Thursday, Dec 12
- Temperature: 85°F (30°C) / 79°F (26°C)
- Weather: Humid with light rain
- Sailing Conditions: Moderate; Waves 1.5–2m
- Tide: High at 8:31 AM (1.93m), Low at 10:48 PM (1.07m)
Friday, Dec 13
- Temperature: 87°F (30°C) / 78°F (26°C)
- Weather: Rainy
- Sailing Conditions: Rough; Waves 2–2.5m
- Tide: High at 9:00 AM (2.20m), Low at 8:29 PM (0.90m)
Saturday, Dec 14
- Temperature: 79°F (26°C) / 78°F (26°C)
- Weather: Thunderstorms
- Sailing Conditions: Rough; Waves 2.5–3m
- Tide: High at 9:39 AM (2.42m), Low at 8:19 PM (0.74m)
Sunday, Dec 15
- Temperature: 83°F (28°C) / 78°F (26°C)
- Weather: Cloudy with showers
- Sailing Conditions: Moderate; Waves 1.5–2m
- Tide: High at 10:24 AM (2.58m), Low at 8:48 PM (0.64m)
What changes across the week
The week starts unsettled but workable: Monday and Tuesday bring rain and showers with moderate seas and waves of 1.5–2m. Wednesday is the calmest window, with partly sunny skies and waves of just 1–1.5m.
Conditions then deteriorate. From Friday the sea turns rough at 2–2.5m, peaking on Saturday with thunderstorms, waves of 2.5–3m and the coolest day of the week at 79°F (26°C). Sunday eases back to moderate seas and cloudy weather with showers.
Who is affected and what it means for your trip
Rough seas matter most on the open-water legs between the mainland and the islands, and on the longer runs out to Koh Tao. On days marked rough, expect a bumpier ride, slower going and a higher chance of delays or cancellations. Passengers prone to seasickness should favour the calm and moderate days, book a lower deck seat where possible, and travel in the morning when winds are often lighter.
Tide times are useful too. The high tides climb steadily through the week, from 1.65m on Wednesday to 2.58m on Sunday, while lows drop to 0.64m. Very low water can affect shallow-draught piers and beach landings, and it shapes swimming and snorkelling plans on arrival.
Routes to check before you book
If your plans fall on a rough day, look at alternatives and connecting options:
- Surat Thani to Koh Samui ferry tickets
- Koh Samui to Koh Phangan ferry crossings
- Koh Phangan to Koh Tao services
- Surat Thani travel and transfer options
Practical booking advice
Build in a buffer around flights and onward connections during the rough spell on Friday and Saturday. Keep your operator's contact details and your booking reference to hand, and check the cancellation and rebooking terms shown at checkout, as these vary by operator and ticket type. If a departure is cancelled for weather, operators normally rebook passengers onto the next available sailing.
Data note: the figures above cover 9–15 December 2024. Live conditions, current departure times and available services should be pulled from the live schedule for your travel date rather than read from this page.
Disclaimer: Weather, sea conditions, and tide information are subject to change. Always check local updates and forecasts before planning activities.
Ready to lock in your crossing around the calmer days? Search availability for your route and travel date.
