Ko Samui (Koh Samui) weather in November

November in Ko Samui: sweltering, soaked, with clean air — a gamble, with 24 rainy days.

Updated September 2026 · climate normals from ERA5 reanalysis

Ko Samui🇹🇭 Thailand · Gulf of Thailand Islands · Island59
  1. 84Jan
  2. 88Feb
  3. 90Mar
  4. 80Apr
  5. 77May
  6. 83Jun
  7. 78Jul
  8. 82Aug
  9. 73Sep
  10. 62Oct
  11. 59Nov
  12. 70Dec

#12 of 12 months in Ko Samui · #1118 of 1413 destinations to visit in November · comfort 59/100 (tier D)

Days
30°C
Nights
25°C
Wet days
24
Sun
8.2 h
Humidity
81%
Daylight
12 h
Ko Samui, Thailand
Photo: Tom Lorber · Pexels

Traveller notes on Ko Samui in November

Other months in Ko Samui

Regulars are consistent this month runs genuinely dry and hot overall, sunshine the default, with only occasional midday-to-afternoon thunder showers rather than a settled wet stretch - some recent Aprils reportedly saw no rain at all for the entire month. Our row backs that brutally hot, humid read, 31.8C reading as a scorching 39C, over 26.4C nights, with 117.7mm of rain across 11.5 days and humidity at 78 percent. Regulars are consistent this counts as a genuinely great time to visit overall despite the intense heat, water and shade breaks the standard advice for anyone spending real time outdoors at midday. The sea sits at a bath-warm 31.5C. The record: 10.6 hours of sun, a 19.3 kph wind and AQI 49.
DryHotWithOccasionalStormsOnly · April · 1 month ago · Read more on Tripadvisor ↗
Regulars are specific that this island sits on the opposite monsoon cycle from Thailand's west coast - Samui is in its drier season this month while Phuket and Krabi are deep in their wet one, with Phuket averaging roughly 260mm of rain in August against Samui's much lighter total. Our row backs the milder wet read, 76.9mm across a real 17.5 days, alongside intense heat, 33C reading as a hot 38C at 76.6 percent humidity, over 25.7C nights. Regulars describe the typical shower as brief, often a 5-20 minute early-evening burst rather than a day-ruining event, with the sea staying calm and glassy for water activities most of the month regardless. The sea holds a warm 30.2C. The record: 9.6 hours of sun, a 23.5 kph wind and one of the cleanest air readings in this project, AQI 27.
DrySideOfThailandWhilePhuketIsWet · August · 1 month ago · Read more on Tripadvisor ↗
Koh Samui-forum threads on June weather describe a reliable, easy pattern: sunny mornings, building cloud through the afternoon, and an occasional shower that posters call a genuine blessing rather than a disruption, since it cools things down without stopping swimming or beach time. All-day, non-stop rain is described as rare rather than typical. June and July together sit inside the island's low-rain season on the Gulf coast, seas calm and generally good for boat trips. Regulars note it runs warmer than the cooler stretch of the year, though most call it manageable, April and May singled out as the actually punishing months. Crowds are consistently described as noticeably thinner than the December-to-March peak season, a real upside for anyone prioritizing quieter beaches over a guaranteed clear forecast. The record: 33.4C days feeling like a punishing 38C, 25.6C nights, 75mm across 17.1 days, 76 percent humidity, a 30.6C sea and 9.6 hours of sun.
ChawengJuneRegular · June · 1 month ago · Read more on tripadvisor.co.nz ↗
January on Samui is the turn out of the island's wet season - which here runs roughly October to the end of December, out of step with most of Thailand - into the cool dry stretch that lasts to March. Being the tail end, it is variable: regulars describe hits and misses with plenty of sun between them, and say the bad weather is usually a short heavy shower followed by sunshine rather than anything prolonged. Our row's 100mm across 9.8 days is that pattern. The part worth planning for is the sea, which can be rough in January, particularly on the east coast, making swimming awkward unless you are on a protected beach - Choeng Mon is the one they name. It is also less humid than later in the year. The record: 29C days that feel like 33C, 24.6C nights and a 28C sea.
ChoengMonWhenItsRough · January · 1 month ago · Read more on Tripadvisor ↗

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Ko Samui climate normals — November

Daytime high30°C / 85°F🔥 sweltering
Nighttime low25°C / 76°F
Feels like (high)35°C / 95°F
Sea temperature30°C / 85°F♨️ bath-warm
Rainfall315 mm / 12.4 in⛈ soaked
Rainy days24 days
Humidity81%💦 very humid
Dew point25°C / 76°F
Sunshine8.2 h/day
Daylight11.7 h
Wind21 km/h / 13 mph
Air quality (US AQI)41🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Ko Samui in November

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Quietone of its worst months for weather(estimated)

JFMAMJJASOND

Peak crowdsBusyShoulder seasonQuiet

Best months for Ko Samui's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Toughest weatherKo Samui's weather peaks January–March.

JFMAMJJASOND

Best weatherFair weatherToughest weather

What's on in Ko Samui in November

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Season

    Northeast monsoon

    15 Oct – 31 Dec · usuallyRisk

    The Gulf's wet season proper: days of rain, water across the ring road in places, and flights and ferries cancelled in the worst of it. The island runs at half staff and half price.

  • Festival

    Loy Krathong

    5–30 Nov · usuallyLights & fire

    Baskets and candles floated off the beaches at the full moon of the twelfth lunar month, in the middle of the island's wettest weeks. A wet-season evening that is worth the wet season. Source ↗

  • Season

    Wet season

    MonsoonRisk

    24 rainy days and about 315 mm in the month — the real kind of rainy season, not afternoon showers.

    from the climate normals

What's on around the world in November →

Nearby, and something's on

Within 300 km of Ko Samui — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Ko Samui?

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Ko Samui in November — FAQ

Is November a good time to visit Ko Samui?
November in Ko Samui: sweltering, soaked, with clean air — a gamble, with 24 rainy days. It ranks #12 of 12 months for Ko Samui on SeasonMap's comfort score (59/100).
What is the weather like in Ko Samui in November?
In November, Ko Samui averages a daily high of 29.7°C and a low of 24.6°C, with about 315.2 mm of rain over roughly 24 rainy days.
What is the air quality in Ko Samui in November?
Ko Samui has a mean US Air Quality Index of about 41 in November.

Within 300 km: Khao Sok's Morning mist on Cheow Lan around 1 Nov – 15 Feb, and Krabi's Loy Krathong around 5–30 Nov.