Koh Samui in November: Weather, Rain and What to Do

November is Koh Samui's wettest month of the year — and the only one when Ang Thong National Park is completely closed. That doesn't mean the island shuts down: it stays warm between showers, the sea is still pleasant for swimming, and Loy Krathong, one of Thailand's most beautiful festivals, falls right in this window.

At a glance

Weather in November

With around 440mm of rainfall over roughly 17 rain days, November is the wettest month of the year on Koh Samui according to the climate normals — wetter even than October. Showers still tend to arrive in heavy, time-limited bursts, but they're more frequent and the overall mood is cloudier. The northeast monsoon also brings more wind and swell to the Gulf side during this period, which is exactly why the authorities consider the sea too unsafe for tour boats to Ang Thong right now. For the monsoon pattern behind this, see our article Koh Samui weather and the truth about the rainy season. Worth packing: light rain protection and waterproof pouches for your phone and camera, especially if boat trips are on the itinerary.

What you can do in November – and what you can't

The key restriction first: Ang Thong National Park is officially closed from 1 November to 15 December 2026, with no tours running there during this period. Full background in our Ang Thong article.

Snorkelling and boat trips are still possible — just to other destinations, such as a day trip to Koh Nang Yuan and Koh Tao. Build in some flexibility, though: with strong north-east winds and high waves, boat trips in November can be postponed or cancelled at short notice.

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More than ever in November, it pays to check the forecast close to departure and keep a backup plan. A good fallback for wind or rain is a full-day island tour with temple stops that runs mostly in an air-conditioned vehicle:

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For beach days, the north coast (Maenam, Bophut) usually remains the calmer choice, while Chaweng and Lamai on the east side sit more directly in the path of the northeast monsoon. More ideas for rainy days in our Top 10 rainy day activities — from air-conditioned malls to a Thai massage or spa session that works regardless of the forecast.

Festivals and events in November

The lantern festival Loy Krathong falls on the full moon of Tuesday 24 November in 2026 — one of the most beautiful festivals of the year, when small banana-leaf boats carrying a candle and incense are floated on water. On Koh Samui, Chaweng Lake, Lamai Lagoon and the beach near the Big Buddha are popular spots, more in our Top 10 events in Thailand. The island noticeably fills up around this weekend, so book accommodation early if your visit lines up with it. Outside that weekend, though, November remains one of the more affordable months for flights and hotels — see our article Cost of a holiday on Koh Samui for typical prices.

Fruit in season

November marks the start of the main soursop season (Thai: Thurian Thet), running through to around February — usually turned into shakes or juice rather than eaten fresh. The smaller winter pineapple harvest also continues. More in our Top 10 fruits in Thailand.

Frequently asked questions

Does it rain a lot on Koh Samui in November?

Yes, November is statistically the wettest month of the year, with around 440mm of rainfall over about 17 rain days. Showers are usually time-limited but occur more often than in the preceding months.

Is November a good time to visit Koh Samui?

It can be, for budget travellers and anyone keen to experience Loy Krathong — prices are low and crowds thin outside the festival weekend. If Ang Thong National Park is a must-see for you, or you need reliably dry weather, pick a different month.

Why is Ang Thong National Park closed in November?

The park authority closes Ang Thong from 1 November to 15 December 2026 because the northeast monsoon makes the sea roughest and least safe for the small tour boats during this window.

Can you still snorkel or take boat trips in November?

Yes, just not to Ang Thong. Day trips to Koh Nang Yuan and Koh Tao, or island tours with temple visits, run as normal whenever the weather allows.

The rain eases gradually in December, ahead of the high season starting in January; see how November builds up in October. For the full-year overview, read The best time to visit Koh Samui.