Koh Phangan Rainy Season: Months, Ferries and What to Do

Featured image: Fabio Achilli from Milano, Italy, CC BY 2.0, via Wikimedia Commons.

Quick answer: the Koh Phangan rainy season

The main Gulf monsoon runs from about October to December. November is the wettest month, with rain on roughly 17 days. A lighter, showery period runs from about May to September. Rain rarely cancels plans. Wind and waves do. For the broader month-by-activity view, start with our guide to the Best Time to Visit Koh Phangan: Month-by-Month Guide (Rain, Ferries, Full Moon). Verdict: go if you want quiet beaches, yoga and waterfalls, and you can tolerate rough crossings.

Two wet periods: Gulf monsoon and showery summer

Koh Phangan has two wet spells, and they behave differently. From about October to December, the north-east monsoon brings heavy showers, thunderstorms and a few all-day rain days. Most monsoon rain falls in bursts lasting an hour or two. From May to September, rain comes mainly as short afternoon showers. Mornings are often sunny. Daytime highs stay near 29°C (84°F) to 33°C (91°F) all year. Sea temperature holds at about 28°C (82°F) to 30°C (86°F), so swimming works in every month. Figures here use 1991–2020 averages for the Koh Samui weather station, about 20 km south of the island. Check the Thai Meteorological Department forecasts before travel, because single years differ.

Month-by-month: rain, sea and what to expect

Use this table as a planning guide. For more detail, see our Koh Phangan weather reference. Rainfall figures come from the Koh Samui station and are rounded. Ferry notes are qualitative.

Why Phuket's wet season is not Koh Phangan's

Phuket and the Andaman coast get the south-west monsoon first. Their wet months run roughly from May or June to October, with September and October the wettest. The Gulf islands are sheltered from that system. Koh Phangan's heavy rain arrives later, from about October. In July and August the island is usually hot and mostly sunny, with 102 to 117 mm of rain a month. Do not assume Phuket weather applies here.

Will my boat or ferry run? Rain vs wind and waves

Light rain rarely stops boats. Wind and waves decide. Operators cancel when the sea is rough or a marine warning is in force. Crossings from Koh Samui, Surat Thani (via Donsak) and Koh Tao can be delayed in November and December. Raja and Lomprayah ferries from Donsak occasionally cancel or delay in those months. The north-east monsoon makes the east coast rougher between November and January. Thong Sala and Srithanu on the west coast usually stay calmer. On west and south beaches, low tide can leave very shallow water. Leave a spare day before any international flight. Check the Gulf shipping forecast and warnings from the Thai Meteorological Department. In an emergency, Tourist Police answer on 1155.

Ang Thong and other seasonal closures

Ang Thong Marine Park closes every year from 1 November to 15 December, with the last tour day on 31 October. Confirm dates with the national park authority before booking, because closures can shift. Tropical storms are rare. Tropical Storm Pabuk in January 2019 closed the park and cancelled ferries to Koh Samui. Land activities carry on. Waterfalls at Phaeng, Than Sadet and Wang Sai flow strongest after monsoon rain, but check path safety first. The Full Moon Party runs in every season, and a 24 November date is listed at Haad Rin. See the full list of Full Moon Party Dates: Koh Phangan Schedule, Shifts and Tips and check the official party site for updates.

Best things to do in the rainy season

Plan around the weather, not against it. Yoga, spa days and waterfall visits suit wet weeks. Evening markets such as Big C Evening Market and Thong Sala Saturday Walking Street keep running on listings seen in November. For nightlife, the Half Moon Festival lists dates, and our Half Moon Party guide explains the format. Verify any date before travel. Dry-season diving sites also remain possible when the sea allows. A Koh Tao and Koh Nang Yuan day trip was listed from ฿2,200 per adult in November 2026 as a closure alternative.

Costs, deals and booking flexibility

Rainy months are low season, so rooms are cheaper and the island is quieter. No official swing figure is published, so compare live rates for your dates against a January to April stay. Prices change by operator. As a reference point, Half Moon Festival tickets were listed from ฿1,300 per person in November 2026. Choose rooms and tours with flexible cancellation. Book boat days early in your stay so there is room to move them if the sea turns.

Where to stay and how to get around in wet weather

West-coast bases such as Thong Sala and Srithanu tend to have calmer water in the north-east monsoon. East-coast beach stays can be rough from November to January. Pick covered or indoor-friendly resorts for long rain days. Wet hill roads are risky on scooters, so use taxis on all-day rain days. Pack a rain jacket, dry bag, shoes with grip and motion-sickness tablets for ferries. For showery months from May to September, add a compact umbrella, quick-dry clothes and insect repellent.

Who should go and who should skip it

First-timers who want calm seas should pick July or August. Yoga and retreat travelers, budget travelers and waterfall hunters suit October to November. Party travelers can time a stay to a Full Moon week in any month. Beach-only travelers and families with young children may prefer January to April. Anyone with a tight international flight connection after a ferry should skip November and early December, or add a buffer day.

Mistakes to avoid

Avoid assuming Phuket weather applies to Koh Phangan. Avoid booking non-refundable boat days late in your stay. Avoid scooters on wet hill roads. Avoid tight flight connections after a ferry. Avoid booking east-coast beach stays in rough-sea months. Re-check closure dates, ferry operators and rainfall figures before you travel, as they change.

• Phuket's wet months are not Koh Phangan's
• Book boat days early, with free cancellation
• Skip scooters on wet hill roads
• Add a buffer day before flights
• Choose west-coast bases in November