Fullerton Weather in December
Average highs run from 42°F on December 1 to 34°F on December 31, and lows from 21°F to 14°F. Normal precipitation for the month is 0.95 in over about 6 wet days.
December day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
December at a glance
- Average high
- 37°F
- Average low
- 17°F
- Precipitation
- 0.95 in
- Snowfall
- 5.0 in
- Record high
- 78°FDec 6, 1939
- Record low
- -29°FDec 10, 1919
- Chance of a freeze
- 100%
- Daylight
- 9 h 24 min to 9 h 14 min
- Cloud cover
- 60%
- Humidity
- 77%
- Dew point
- 20°F
- Wind
- 11.6 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Dec 1 | 42°F | 21°F | 67°F 1998 | -5°F 1985 | 18% | 11% |
| Dec 2 | 41°F | 20°F | 69°F 1998 | -11°F 1919 | 18% | 11% |
| Dec 3 | 41°F | 20°F | 68°F 1956 | -17°F 1919 | 18% | 12% |
| Dec 4 | 41°F | 20°F | 69°F 1959 | -9°F 1902 | 18% | 12% |
| Dec 5 | 40°F | 19°F | 65°F 1989 | -5°F 1950 | 18% | 12% |
| Dec 6 | 40°F | 19°F | 78°F 1939 | -14°F 1950 | 19% | 12% |
| Dec 7 | 39°F | 19°F | 64°F 1988 | -13°F 1972 | 19% | 12% |
| Dec 8 | 39°F | 18°F | 68°F 1984 | -18°F 1917 | 19% | 13% |
| Dec 9 | 39°F | 18°F | 71°F 1970 | -19°F 1919 | 19% | 13% |
| Dec 10 | 38°F | 18°F | 69°F 1957 | -29°F 1919 | 19% | 13% |
| Dec 11 | 38°F | 18°F | 69°F 1921 | -10°F 1994 | 19% | 13% |
| Dec 12 | 38°F | 17°F | 70°F 1921 | -21°F 1932 | 19% | 13% |
| Dec 13 | 37°F | 17°F | 60°F 1957 | -23°F 1917 | 19% | 13% |
| Dec 14 | 37°F | 17°F | 61°F 1988 | -27°F 1901 | 19% | 13% |
| Dec 15 | 37°F | 17°F | 74°F 1939 | -25°F 1901 | 19% | 14% |
| Dec 16 | 36°F | 17°F | 68°F 1939 | -23°F 1914 | 19% | 14% |
| Dec 17 | 36°F | 16°F | 73°F 1962 | -17°F 1989 | 19% | 14% |
| Dec 18 | 36°F | 16°F | 69°F 1980 | -21°F 2016 | 19% | 14% |
| Dec 19 | 36°F | 16°F | 70°F 1979 | -26°F 1989 | 20% | 14% |
| Dec 20 | 35°F | 16°F | 60°F 1979 | -26°F 1989 | 20% | 14% |
| Dec 21 | 35°F | 16°F | 63°F 1933 | -28°F 1916 | 20% | 14% |
| Dec 22 | 35°F | 15°F | 73°F 1933 | -27°F 1989 | 20% | 14% |
| Dec 23 | 35°F | 15°F | 62°F 2025 | -27°F 1989 | 20% | 14% |
| Dec 24 | 35°F | 15°F | 67°F 1964 | -24°F 1920 | 20% | 14% |
| Dec 25 | 35°F | 15°F | 64°F 2025 | -19°F 1983 | 20% | 15% |
| Dec 26 | 34°F | 15°F | 63°F 1963 | -14°F 1962 | 20% | 15% |
| Dec 27 | 34°F | 15°F | 66°F 2025 | -22°F 1924 | 20% | 15% |
| Dec 28 | 34°F | 15°F | 64°F 2025 | -24°F 1924 | 20% | 15% |
| Dec 29 | 34°F | 14°F | 61°F 2002 | -23°F 1917 | 20% | 15% |
| Dec 30 | 34°F | 14°F | 70°F 1904 | -15°F 1916 | 20% | 15% |
| Dec 31 | 34°F | 14°F | 72°F 1904 | -24°F 1967 | 19% | 15% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CST).
- December 1
- sunrise 7:39 AM, sunset 5:03 PM
- December 31
- sunrise 7:58 AM, sunset 5:12 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00253185 (Genoa 2 W), public domain. Records: NOAA GHCN-Daily, station USC00250070, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: 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.