How warm is it in Koh Samui in December?

Daytime highs averaged 28.0 °C, night-time lows 26.8 °C. The highest value of the past 10 years was 29.6 °C (20 Dec 2023), the lowest 24.2 °C (19 Dec 2017).

How often does it rain in Koh Samui in December?

On average there were 19.3 rain days (at least 1 mm) with 370 mm of precipitation in total.

🇹🇭 Weather in Koh Samui in December

This is what the weather in Koh Samui (Thailand) was like in December in 2016–2025.

Key facts at a glance

Prevailing weather: Rain

Avg. daytime high

28.0 °C

27.6 °C – 28.7 °C

Avg. night-time low

26.8 °C

26.4 °C – 27.5 °C

Avg. rain days in period

19.3

62 % of days · ≥ 1.0 mm

Avg. precipitation in period

370 mm

132 mm – 686 mm

Avg. cloud cover

78 %

This data source has no sunshine hours – average cloud cover shown instead.

Avg. sea temperature

–

Sea temperature unavailable for today (daily limit).

Extremes: Highest temperature 29.6 °C (20 Dec 2023) · Lowest temperature 24.2 °C (19 Dec 2017) · Avg. daily peak wind 23 km/h

Weather mix of all days

18Sunny
47Partly cloudy
52Cloudy
63Light rain
130Rain

Summary

On average 28.0 °C during the day and 26.8 °C at night.
On average 19.3 rain days (Rain day = at least 1.0 mm of precipitation) with 370 mm of precipitation in total.
Prevailing: Rain.
Warmest year: 2023 (avg. 28.7 °C), coolest: 2021 (avg. 27.6 °C).
Wettest year: 2016 (686 mm), driest: 2019 (132 mm).
Extremes: 29.6 °C on 20 Dec 2023 and 24.2 °C on 19 Dec 2017.

Overall values from all 10 years. How is this calculated?

Temperatures per year

Average over your travel period

Precipitation & rain days

Year by year

2025
Avg. max27.8°Avg. min26.4°
Rain days
14 Rain days
Precipitation
186 mm
Avg. cloud cover
66 % cloudy
Sea temperature
–
Max 28.5 °C · Min 25.6 °C
2024
Avg. max28.3°Avg. min27.1°
Rain days
16 Rain days
Precipitation
627 mm
Avg. cloud cover
84 % cloudy
Sea temperature
–
Max 29.1 °C · Min 25.7 °C
2023
Avg. max28.7°Avg. min27.5°
Rain days
23 Rain days
Precipitation
168 mm
Avg. cloud cover
75 % cloudy
Sea temperature
–
Max 29.6 °C · Min 26.2 °C
2022
Avg. max27.8°Avg. min26.6°
Rain days
19 Rain days
Precipitation
356 mm
Avg. cloud cover
85 % cloudy
Sea temperature
–
Max 28.7 °C · Min 25.9 °C
2021
Avg. max27.6°Avg. min26.4°
Rain days
18 Rain days
Precipitation
189 mm
Avg. cloud cover
71 % cloudy
Sea temperature
–
Max 28.3 °C · Min 25.2 °C
2020
Avg. max27.8°Avg. min26.6°
Rain days
19 Rain days
Precipitation
539 mm
Avg. cloud cover
81 % cloudy
Sea temperature
–
Max 28.4 °C · Min 25.6 °C
2019
Avg. max27.7°Avg. min26.5°
Rain days
16 Rain days
Precipitation
132 mm
Avg. cloud cover
61 % cloudy
Sea temperature
–
Max 28.6 °C · Min 25.7 °C
2018
Avg. max28.3°Avg. min27.4°
Rain days
24 Rain days
Precipitation
504 mm
Avg. cloud cover
86 % cloudy
Sea temperature
–
Max 29.1 °C · Min 26.7 °C
2017
Avg. max27.7°Avg. min26.5°
Rain days
18 Rain days
Precipitation
317 mm
Avg. cloud cover
75 % cloudy
Sea temperature
–
Max 28.7 °C · Min 24.2 °C
2016
Avg. max27.9°Avg. min26.8°
Rain days
26 Rain days
Precipitation
686 mm
Avg. cloud cover
93 % cloudy
Sea temperature
–
Max 28.6 °C · Min 25.9 °C

Frequently asked questions

How warm is it in Koh Samui in December?: Daytime highs averaged 28.0 °C, night-time lows 26.8 °C. The highest value of the past 10 years was 29.6 °C (20 Dec 2023), the lowest 24.2 °C (19 Dec 2017).
How often does it rain in Koh Samui in December?: On average there were 19.3 rain days (at least 1 mm) with 370 mm of precipitation in total.

Check your exact travel dates

Choose your travel period – we show the weather for exactly those days.

Data sources

Weather data: Data obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program
Reanalysis (weather model constrained by observations) on a coarse grid of about 50 km. Values represent a large area and can differ from local conditions, especially on islands, coasts and in mountains. No sunshine duration.
Reanalysis (weather model constrained by observations)
Reanalysis values represent a grid cell (approx. 25–50 km) and may differ from local measurements on coasts, islands and in mountains.
Sea temperature: MUR SST data were provided by JPL under support by NASA MEaSUREs program; accessed via NOAA CoastWatch ERDDAP
Daily multi-scale ultra-high resolution (≈ 1 km) analysis of satellite measurements (infrared, microwave) and in-situ data. Represents the foundation temperature below the daily warm surface layer. (Satellite and in-situ analysis)
Place search: Natural Earth (public domain) · GeoNames (CC BY 4.0) / OpenStreetMap (ODbL)