Upland Weather in December
Average highs run from 69°F on December 1 to 67°F on December 31, and lows from 45°F to 44°F. Normal precipitation for the month is 1.89 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
- 67°F
- Average low
- 44°F
- Precipitation
- 1.89 in
- Record high
- 93°FDec 4, 1979
- Record low
- 22°FDec 22, 1990
- Chance of a freeze
- 21%
- Daylight
- 10 h 03 min to 9 h 55 min
- Cloud cover
- 43%
- Humidity
- 54%
- Dew point
- 30°F
- Wind
- 6.9 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Dec 1 | 69°F | 45°F | 86°F 1959 | 28°F 1931 | 16% |
| Dec 2 | 69°F | 45°F | 88°F 1958 | 26°F 1936 | 16% |
| Dec 3 | 69°F | 45°F | 92°F 1958 | 27°F 1934 | 16% |
| Dec 4 | 68°F | 44°F | 93°F 1979 | 28°F 1948 | 17% |
| Dec 5 | 68°F | 44°F | 90°F 1979 | 26°F 1948 | 17% |
| Dec 6 | 68°F | 44°F | 89°F 1938 | 27°F 1920 | 17% |
| Dec 7 | 68°F | 44°F | 86°F 1938 | 25°F 1951 | 17% |
| Dec 8 | 67°F | 44°F | 89°F 1938 | 25°F 1951 | 17% |
| Dec 9 | 67°F | 44°F | 84°F 1975 | 23°F 1951 | 17% |
| Dec 10 | 67°F | 44°F | 86°F 1958 | 26°F 1951 | 17% |
| Dec 11 | 67°F | 44°F | 88°F 1958 | 27°F 1916 | 18% |
| Dec 12 | 67°F | 43°F | 85°F 1895 | 25°F 1949 | 18% |
| Dec 13 | 67°F | 43°F | 85°F 1958 | 24°F 1901 | 18% |
| Dec 14 | 66°F | 43°F | 84°F 1953 | 25°F 1901 | 18% |
| Dec 15 | 66°F | 43°F | 85°F 1980 | 27°F 1948 | 18% |
| Dec 16 | 66°F | 43°F | 85°F 1980 | 27°F 1915 | 18% |
| Dec 17 | 66°F | 43°F | 86°F 1979 | 26°F 1916 | 18% |
| Dec 18 | 66°F | 43°F | 84°F 1917 | 26°F 1924 | 18% |
| Dec 19 | 66°F | 43°F | 85°F 1985 | 26°F 1897 | 18% |
| Dec 20 | 66°F | 43°F | 84°F 1985 | 28°F 1897 | 18% |
| Dec 21 | 66°F | 43°F | 84°F 1917 | 23°F 1968 | 18% |
| Dec 22 | 66°F | 43°F | 81°F 1960 | 22°F 1990 | 18% |
| Dec 23 | 66°F | 43°F | 82°F 1989 | 26°F 1990 | 18% |
| Dec 24 | 66°F | 43°F | 86°F 2005 | 24°F 1953 | 18% |
| Dec 25 | 66°F | 43°F | 85°F 1980 | 25°F 1924 | 18% |
| Dec 26 | 66°F | 43°F | 87°F 1980 | 25°F 1924 | 18% |
| Dec 27 | 67°F | 44°F | 82°F 1956 | 24°F 1962 | 18% |
| Dec 28 | 67°F | 44°F | 85°F 1956 | 24°F 1954 | 18% |
| Dec 29 | 67°F | 44°F | 88°F 1980 | 24°F 1954 | 17% |
| Dec 30 | 67°F | 44°F | 85°F 1980 | 24°F 1918 | 17% |
| Dec 31 | 67°F | 44°F | 82°F 1897 | 25°F 1918 | 17% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PST).
- December 1
- sunrise 6:38 AM, sunset 4:41 PM
- December 31
- sunrise 6:56 AM, sunset 4:51 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00003102 (Ontario Intl AP), public domain. Records: NOAA GHCN-Daily, station USC00047050, 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.