Santa Helena Weather in December

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

Average highs run from 31°C on December 1 to 31°C on December 31, and lows from 23°C to 25°C. Normal precipitation for the month is 171 mm over about 16 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: 31°C
Average low: 24°C
Precipitation: 171 mm
Reanalysis high: 38°CDec 21, 2011
Reanalysis low: 14°CDec 14, 2010
Daylight: 13 h 34 min to 13 h 39 min
Cloud cover: 67%
Humidity: 67%
Dew point: 21°C
Wind: 10.8 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	31°C	23°C	36°C 1995	15°C 2001	48%
Dec 2	31°C	23°C	37°C 1998	17°C 2011	49%
Dec 3	31°C	23°C	37°C 2007	18°C 2018	49%
Dec 4	31°C	23°C	36°C 2007	17°C 2008	50%
Dec 5	31°C	24°C	37°C 1999	19°C 2008	51%
Dec 6	31°C	24°C	34°C 1993	19°C 2019	51%
Dec 7	31°C	24°C	35°C 1995	19°C 2019	52%
Dec 8	31°C	24°C	36°C 1998	18°C 2018	51%
Dec 9	31°C	24°C	35°C 1994	20°C 2003	52%
Dec 10	31°C	24°C	35°C 1994	18°C 2003	53%
Dec 11	31°C	24°C	35°C 2018	21°C 2004	52%
Dec 12	31°C	24°C	35°C 2018	20°C 2009	51%
Dec 13	31°C	24°C	35°C 1998	16°C 2010	51%
Dec 14	31°C	24°C	36°C 1998	14°C 2010	52%
Dec 15	31°C	24°C	37°C 2006	18°C 2016	53%
Dec 16	31°C	24°C	37°C 2006	18°C 2000	53%
Dec 17	31°C	24°C	38°C 1995	16°C 2000	52%
Dec 18	31°C	24°C	36°C 1995	18°C 2000	51%
Dec 19	31°C	24°C	36°C 2018	21°C 1998	50%
Dec 20	31°C	24°C	37°C 2011	21°C 1998	50%
Dec 21	31°C	24°C	38°C 2011	20°C 2020	51%
Dec 22	31°C	24°C	37°C 2011	19°C 2019	51%
Dec 23	31°C	24°C	38°C 2011	18°C 1998	52%
Dec 24	31°C	24°C	36°C 1994	20°C 1998	53%
Dec 25	31°C	25°C	36°C 1994	21°C 2019	54%
Dec 26	31°C	25°C	37°C 2012	21°C 2001	55%
Dec 27	31°C	25°C	37°C 2013	20°C 1991	55%
Dec 28	31°C	25°C	37°C 2011	22°C 1991	55%
Dec 29	31°C	25°C	38°C 2008	21°C 1993	53%
Dec 30	31°C	25°C	37°C 2008	18°C 1993	52%
Dec 31	31°C	25°C	35°C 2008	21°C 1993	52%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (GMT-3).

December 1: sunrise 5:40 AM, sunset 7:14 PM
December 31: sunrise 5:51 AM, sunset 7:30 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 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.