Koh Samui in November — Weather, Rain & Is It Worth It?

Is November a Good Time to Visit Koh Samui?

No, not for guaranteed sun — November is Koh Samui’s wettest month of the year, averaging roughly 445 mm of rain across 16 rain days, per Climates to Travel’s 1991-2020 climate normals (checked Sep 2026). It still works for travelers chasing low prices, thin crowds and jungle scenery at its greenest, provided the trip plan stays flexible and leans on the island’s sheltered west and south coasts rather than the exposed east side.

Key takeaways

• November rainfall (445 mm) beats October (295 mm) and December (265 mm) by a wide margin — the honest wettest month on the calendar
• Sunshine still averages 6.0 hours a day, more than October’s 4.5 — rain comes as hard bursts, not a solid gray ceiling
• West/south coast beaches (Lipa Noi, Taling Ngam, Nathon, Thong Krut) stay sheltered while the northeast monsoon pounds Chaweng and Lamai
• Waterfalls run at their fullest of the year — the one unambiguous upside of a November trip
• Rates sit at their annual low, then flip hard in the last week of December

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Koh Samui Weather in November — Rain, Sun and Temperature

November’s numbers make the case on their own: 24.1-29.7°C, 445 mm of rain and a 29.0°C sea, against a noticeably drier October and December on either side. The table below uses the same 1991-2020 normals as this site’s best time to visit hub, cross-checked against the Thai Meteorological Department.

November and October share the same 16 rain days, but November dumps roughly 50 percent more water — the difference is intensity, not frequency. Temperature barely moves across the shift (26.9°C mean in November), so the weather risk here is entirely about rain and sea state, never about heat or cold.

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What 445 mm of Rain Actually Feels Like

445 mm across 16 days means most of November’s rain arrives as short, hard downpours rather than a week of drizzle. A typical day still opens sunny, clouds build by early afternoon, and a 20-60 minute deluge breaks before clearing back to sun or bright haze — the same pattern this site’s rainy season guide documents for the wider monsoon, just turned up in volume for November specifically. The tell is the sunshine number: 6.0 hours a day beats October’s 4.5, so November is not the grayer month — it is the harder-hitting one.

The exception is a tropical depression sitting over the Gulf, bringing 24-48 hours of near-continuous rain. These systems cluster in November, cancel day-trip boats, and mark the difference between a wet afternoon and a written-off day. Check Thai Meteorological Department warnings before locking in a boat trip or ferry crossing.

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Which Beaches Work in November

The west and south coasts stay sheltered in November, while the east coast takes the direct hit from the northeast monsoon building toward its peak. Lipa Noi, Taling Ngam, Nathon and Thong Krut all face west or southwest, out of the main swell path, and stay swimmable on days the east side is red-flagged. Chaweng and Lamai, facing open Gulf water, see the year’s roughest surf and most frequent red flags in November — see this site’s sea conditions by month guide for the full coast-by-coast breakdown.

Book a west or south-coast hotel, or plan an afternoon there, rather than assuming an east-coast resort’s beach stays usable every day. Nathon, the ferry port town, doubles as a sheltered base away from the swell hitting Chaweng and Lamai.

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Waterfalls at Peak Flow

November’s rain has one clear upside: the island’s waterfalls run at their fullest of the year. Na Muang Waterfalls — home to the accessible Purple Waterfall pool and Samui’s tallest 80m cascade — carries far more volume than the trickle it reduces to by March-April. Hin Lad Waterfall, reached via a riverside path near Nathon, and Khun Si Waterfall, tucked above Bophut with tiered pools, are both at their most photogenic in exactly this window.

The trade-off is access: trail approach paths turn muddy and rocks around the pools get slick, so plan for wet feet and a slower pace rather than a quick in-and-out visit. None of the three closes for rain, but all three reward sturdy sandals over flip-flops in November.

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Hiking in November — What Still Works

Most of Koh Samui’s jungle trails stay open through November, but slippery footing rules out anything steep, exposed or guide-required. The Hin Lad Waterfall Trail (2.6 km, riverside, gentle grade) and the accessible lower stretch of the Na Muang Waterfalls Trail (3.9 km to the Purple Waterfall pool) stay genuinely walkable in November rain, since both follow well-trodden, mostly shaded ground. The Secret Buddha Garden Trail up Pom Mountain is also doable, just muddier and slower than in the dry season.

Skip the harder routes: the Khun Si Waterfall Trail’s steep jungle path and the Khao Pom Summit Trek — Samui’s highest point at 635m, guide-required and “challenging” even dry — turn genuinely risky when wet. Save both for the December-April dry window.

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Sea Conditions and Box Jellyfish in November

The sea itself stays warm at 29.0°C, but wave state is the real November risk, not temperature. Chaweng and Lamai see their roughest surf and most frequent red flags of the year as the northeast monsoon builds toward its December peak, while north and west-coast water stays merely choppy — the same pattern this site’s sea conditions by month guide tracks coast by coast.

November also sits inside the island’s elevated box jellyfish window. Sources disagree on the exact peak, but several beach entries on this site log “occasional” sightings specifically October-December, overlapping with November. Confirmed highest-risk at Chaweng and Lamai — check posted signs or ask at a beachfront resort before swimming, and treat vinegar (never fresh water) as the first-aid basic if stung.

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Events in November

Two events land in November worth building a trip around. Loy Krathong, Thailand’s festival of lights, falls on 25 November 2026 — floating krathong offerings appear on beaches and canals island-wide, and it’s one of the few nights Samui’s usually quiet November beaches fill with locals and visitors alike. The Koh Phangan Full Moon Party also falls close by, on 24 November 2026, so expect a busier-than-usual week for ferries and transfers around both dates. See this site’s best time to visit hub for the fuller year-round events table.

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Prices, Crowds and the Late-December Reversal

November sits at the low point of Koh Samui’s annual price cycle — hotel and villa rates typically run 20-40 percent below the December-February peak, and beaches, restaurants and dive boats all see a fraction of high-season crowds. This is the flip side of the rain: fewer people are willing to book a wettest-month trip, so anyone who does gets the emptiest version of the island outside of true low season.

That window closes fast: rates and demand reverse sharply in the last week of December, once Christmas and New Year travelers arrive — the busiest, most expensive stretch of the year. A November booking can cost noticeably less than the same room booked for 27 December. Travelers wanting low prices without full monsoon risk should also compare the shoulder season window either side of November.

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What to Pack for Koh Samui in November

Pack a light rain jacket or poncho over a full waterproof shell — most November rain is a 20-60 minute burst, not a daylong soak. A dry bag or waterproof phone pouch matters more this month than any other, since downpours arrive with little warning on a scooter or beach day. Sturdy sandals beat flip-flops for wet waterfall trails, and travel insurance that covers trip disruption (not just medical) is worth having given the higher odds of a cancelled boat trip or ferry delay. Full seasonal packing detail is in this site’s packing list guide.

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FAQ

Is Koh Samui worth visiting in November?

Yes, for travelers prioritizing low prices, thin crowds and full waterfalls over guaranteed sun. November is Koh Samui’s wettest month (~445 mm, 16 rain days), but sunshine still averages 6.0 hours a day and sea temperature holds at 29.0°C. It suits flexible travelers more than anyone locked into a fixed beach-every-day itinerary.

Why is November the wettest month on Koh Samui?

November sits at the peak of the northeast monsoon, which sweeps moisture off the South China Sea onto Thailand’s Gulf coast from roughly October through December. Rainfall builds from October’s 295 mm to November’s 445 mm before easing to December’s 265 mm, per Climates to Travel’s 1991-2020 normals — the single wettest month of the year.

Which beaches are best on Koh Samui in November?

Lipa Noi, Taling Ngam, Nathon and Thong Krut on the west and south coasts stay sheltered from the northeast monsoon swell that hits Chaweng and Lamai directly. A west or south-coast base keeps swimming realistic on days the east coast is red-flagged.

Are Koh Samui’s waterfalls better in November?

Yes. Na Muang, Hin Lad and Khun Si waterfalls all run at their fullest and most photogenic in November, fed directly by the month’s heavy rain. The trade-off is muddier trails and slicker rocks around the pools, so sturdy footwear matters more than usual.

Is it safe to hike on Koh Samui in November?

Gentler trails like the Hin Lad Waterfall Trail and the lower Na Muang Waterfalls Trail stay walkable in November. Steeper, guide-required routes like the Khao Pom Summit Trek and the Khun Si Waterfall Trail get genuinely slippery and are better saved for the December-April dry season.

How much cheaper is Koh Samui in November?

Hotel and villa rates typically run 20-40 percent below the December-February peak in November, reflecting the lowest demand of the year. That gap closes fast: rates and crowds reverse sharply in the last week of December once Christmas and New Year travelers arrive, making late November through mid-December the best value window right before the spike.