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Climate · Koh Samui

Koh Samui in December

Warm and wet, as the days hold steady.

Typical weather, averaged over 30 years

December in Koh Samui is warm: highs near 80°F, lows near 76°F. Rain falls on about four days a week, less often as the month goes on, and daylight holds at about 11 hours 35 minutes.December in Koh Samui is warm: highs near 27°C, lows near 24°C. Rain falls on about four days a week, less often as the month goes on, and daylight holds at about 11 hours 35 minutes.

High
80°F27°Caverage
Low
76°F24°Caverage
Wet days
4a week · 54% of days
Daylight
11h 35mon average

Is December a good time to visit Koh Samui?

A good month, just outside Koh Samui's best months, which run from January to March.

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How December sits in the year

week by week

Temperature

Highs near 80°F in December, against 80°F to 84°F through the year.Highs near 27°C in December, against 27°C to 29°C through the year.

Chance of a wet day

54% of days in December, against 30% to 89% through the year.

Cloud cover

68% cover in December, against 59% to 80% through the year.

Daylight

11h 35m in December, against 11h 35m to 12h 40m through the year.

Week by week, lightly smoothed, with December shaded. The olive line marks the best months. Hover or tap a week for its figures.

Either side

  1. November80°27°low 76°low 24°6 wet days a weekRain on about six days a week.
  2. December80°27°low 76°low 24°4 wet days a weekRain on about four days a week.
  3. January80°27°low 75°low 24°3 wet days a weekRain on about three days a week.

Where Koh Samui sits, in December

Asia/Bangkok
this place
typical high in December 40°F4°C95°F35°C
Sunrise, mid-December
6:28 AMsets 6:02 PM
Above the sea
420 mlow-lying
Latitude
9.5°Nnorthern hemisphere
Nearest of ours
Krabi183 km south-west

The land around Koh Samui, shaded by its typical high in December, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in Thailand in December

high · low · wet days
See December on the planning mapThe whole year in Koh Samui

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest Koh Samui. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (420 m) against the climate model's (71 m).Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (420 m) against the climate model's (71 m). Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.