Ko Samui Weather in December

NASA POWER reanalysis for the half-degree grid cell around Ko Samui, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

Average highs run from 28°C on December 1 to 27°C on December 31, and lows from 27°C to 26°C. Normal precipitation for the month is 245 mm over about 19 wet days.

December day by day

The normal high and low for each date, in °C.

Normal low
Normal high
Reanalysis extreme high
Reanalysis extreme low

December at a glance

Average high: 28°C
Average low: 26°C
Precipitation: 245 mm
Reanalysis high: 30°CDec 5, 2006
Reanalysis low: 22°CDec 24, 1999
Daylight: 11 h 36 min to 11 h 34 min
Cloud cover: 75%
Humidity: 80%
Dew point: 23°C
Wind: 19.8 km/h

Every day of the month

A wet day has at least 1 mm of precipitation in the reanalysis.

Date	Normal high	Normal low	Reanalysis high	Reanalysis low	Chance wet
Dec 1	28°C	27°C	29°C 2006	25°C 1992	74%
Dec 2	28°C	27°C	29°C 2006	25°C 1992	73%
Dec 3	28°C	27°C	29°C 2006	25°C 1992	72%
Dec 4	28°C	27°C	29°C 2006	25°C 1992	72%
Dec 5	28°C	27°C	30°C 2006	26°C 1992	70%
Dec 6	28°C	27°C	29°C 2002	26°C 2019	68%
Dec 7	28°C	27°C	29°C 2015	25°C 1995	67%
Dec 8	28°C	27°C	29°C 2015	25°C 1995	66%
Dec 9	28°C	27°C	29°C 2015	25°C 1992	65%
Dec 10	28°C	27°C	29°C 2014	25°C 2008	65%
Dec 11	28°C	27°C	29°C 2014	25°C 1998	65%
Dec 12	28°C	27°C	29°C 2014	25°C 1998	65%
Dec 13	28°C	27°C	29°C 2012	25°C 1992	64%
Dec 14	28°C	27°C	29°C 2006	25°C 1992	62%
Dec 15	28°C	26°C	29°C 2006	25°C 1992	62%
Dec 16	28°C	26°C	29°C 2006	25°C 1992	60%
Dec 17	28°C	26°C	29°C 1994	25°C 1998	59%
Dec 18	28°C	26°C	28°C 2006	25°C 2005	58%
Dec 19	28°C	26°C	28°C 2020	24°C 2017	56%
Dec 20	28°C	26°C	29°C 2015	24°C 2017	54%
Dec 21	28°C	26°C	29°C 2012	25°C 2017	54%
Dec 22	28°C	26°C	28°C 2012	24°C 1999	53%
Dec 23	28°C	26°C	28°C 2018	23°C 1999	52%
Dec 24	27°C	26°C	29°C 2015	22°C 1999	52%
Dec 25	27°C	26°C	29°C 2012	22°C 1999	50%
Dec 26	27°C	26°C	29°C 2012	23°C 1999	48%
Dec 27	27°C	26°C	29°C 2012	23°C 1999	48%
Dec 28	27°C	26°C	29°C 2012	24°C 1999	47%
Dec 29	27°C	26°C	29°C 2012	24°C 1993	47%
Dec 30	27°C	26°C	29°C 2012	25°C 1993	47%
Dec 31	27°C	26°C	29°C 2012	25°C 1995	46%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (GMT+7).

December 1: sunrise 6:21 AM, sunset 5:57 PM
December 31: sunrise 6:36 AM, sunset 6:10 PM

Every day of December: sun and moon

Other months

Sources

Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.