San José Weather in December

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

Average highs run from 29°C on December 1 to 30°C on December 31, and lows from 23°C to 23°C. Normal precipitation for the month is 21 mm over about 5 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: 29°C
Average low: 23°C
Precipitation: 21 mm
Reanalysis high: 34°CDec 24, 2009
Reanalysis low: 18°CDec 31, 1999
Daylight: 11 h 32 min to 11 h 30 min
Cloud cover: 65%
Humidity: 80%
Dew point: 22°C
Wind: 9.0 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	29°C	23°C	33°C 1991	20°C 2001	24%
Dec 2	29°C	23°C	33°C 1993	20°C 1999	23%
Dec 3	29°C	23°C	33°C 2009	20°C 2001	22%
Dec 4	29°C	23°C	32°C 1994	20°C 2001	22%
Dec 5	29°C	23°C	33°C 1993	21°C 2010	21%
Dec 6	29°C	23°C	33°C 1994	21°C 1996	20%
Dec 7	29°C	23°C	32°C 1993	20°C 2010	20%
Dec 8	29°C	23°C	32°C 1997	20°C 2010	19%
Dec 9	29°C	23°C	33°C 1993	21°C 2010	18%
Dec 10	29°C	23°C	33°C 2009	20°C 2010	18%
Dec 11	29°C	23°C	33°C 1994	19°C 2010	18%
Dec 12	29°C	23°C	33°C 1994	20°C 2017	17%
Dec 13	29°C	23°C	33°C 1994	20°C 2017	17%
Dec 14	29°C	23°C	33°C 1993	19°C 2010	18%
Dec 15	29°C	23°C	33°C 1993	18°C 2010	17%
Dec 16	29°C	23°C	33°C 1994	20°C 1997	17%
Dec 17	29°C	23°C	33°C 1993	18°C 2010	17%
Dec 18	29°C	23°C	33°C 1995	20°C 2010	17%
Dec 19	29°C	23°C	32°C 1994	21°C 2010	16%
Dec 20	29°C	23°C	33°C 1995	20°C 2008	15%
Dec 21	30°C	23°C	33°C 1993	20°C 2008	14%
Dec 22	30°C	22°C	33°C 1993	20°C 2010	13%
Dec 23	30°C	23°C	33°C 1993	20°C 2010	13%
Dec 24	30°C	22°C	34°C 2009	20°C 2010	13%
Dec 25	30°C	23°C	34°C 2009	19°C 1991	12%
Dec 26	30°C	23°C	33°C 1997	20°C 2010	13%
Dec 27	30°C	23°C	33°C 1997	19°C 1999	13%
Dec 28	30°C	23°C	32°C 1992	19°C 1999	13%
Dec 29	30°C	23°C	33°C 2001	19°C 1999	12%
Dec 30	30°C	23°C	32°C 1993	20°C 1999	12%
Dec 31	30°C	23°C	32°C 1995	18°C 1999	11%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (CST).

December 1: sunrise 5:44 AM, sunset 5:16 PM
December 31: sunrise 5:59 AM, sunset 5:29 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 2026-09-26. Sun and moon: computed with the NOAA solar equations and Meeus.