Ontario Weather in December
Average highs run from 43°F on December 1 to 35°F on December 31, and lows from 27°F to 20°F. Normal precipitation for the month is 3.06 in over about 13 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
- 39°F
- Average low
- 23°F
- Precipitation
- 3.06 in
- Snowfall
- 9.7 in
- Record high
- 73°FDec 3, 1982
- Record low
- -17°FDec 22, 1989
- Chance of a freeze
- 100%
- Daylight
- 9 h 28 min to 9 h 19 min
- Cloud cover
- 78%
- Humidity
- 86%
- Dew point
- 26°F
- Wind
- 12.1 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 | 43°F | 27°F | 67°F 1970 | 9°F 1964 | 41% | 18% |
| Dec 2 | 43°F | 27°F | 68°F 1982 | -7°F 1976 | 42% | 18% |
| Dec 3 | 43°F | 27°F | 73°F 1982 | -8°F 1976 | 42% | 19% |
| Dec 4 | 42°F | 27°F | 67°F 1982 | 5°F 1966 | 42% | 19% |
| Dec 5 | 42°F | 26°F | 68°F 2001 | 6°F 1991 | 42% | 20% |
| Dec 6 | 42°F | 26°F | 67°F 1998 | 0°F 1977 | 42% | 20% |
| Dec 7 | 41°F | 26°F | 67°F 1998 | 1°F 1977 | 42% | 20% |
| Dec 8 | 41°F | 25°F | 66°F 1966 | 1°F 2005 | 43% | 21% |
| Dec 9 | 41°F | 25°F | 60°F 1952 | -3°F 1977 | 43% | 21% |
| Dec 10 | 40°F | 25°F | 68°F 1971 | -2°F 1977 | 43% | 22% |
| Dec 11 | 40°F | 25°F | 63°F 2021 | -5°F 1977 | 43% | 22% |
| Dec 12 | 40°F | 24°F | 67°F 2015 | -8°F 1962 | 43% | 23% |
| Dec 13 | 39°F | 24°F | 62°F 2015 | -6°F 1960 | 43% | 23% |
| Dec 14 | 39°F | 24°F | 62°F 1984 | -1°F 1963 | 43% | 24% |
| Dec 15 | 39°F | 24°F | 67°F 1971 | -1°F 1951 | 43% | 24% |
| Dec 16 | 39°F | 23°F | 62°F 1984 | -12°F 1951 | 43% | 25% |
| Dec 17 | 38°F | 23°F | 61°F 1984 | -11°F 1989 | 43% | 25% |
| Dec 18 | 38°F | 23°F | 61°F 1967 | -3°F 1989 | 43% | 25% |
| Dec 19 | 38°F | 23°F | 54°F 1976 | -6°F 1963 | 43% | 26% |
| Dec 20 | 38°F | 22°F | 57°F 1988 | -6°F 1963 | 43% | 26% |
| Dec 21 | 37°F | 22°F | 63°F 1967 | -12°F 1989 | 43% | 27% |
| Dec 22 | 37°F | 22°F | 59°F 1949 | -17°F 1989 | 43% | 27% |
| Dec 23 | 37°F | 22°F | 63°F 2015 | -9°F 1960 | 43% | 28% |
| Dec 24 | 37°F | 21°F | 62°F 1964 | -14°F 1983 | 43% | 28% |
| Dec 25 | 36°F | 21°F | 62°F 1982 | -15°F 2004 | 43% | 28% |
| Dec 26 | 36°F | 21°F | 65°F 2016 | -8°F 1983 | 43% | 29% |
| Dec 27 | 36°F | 21°F | 64°F 2015 | -8°F 1950 | 43% | 29% |
| Dec 28 | 36°F | 20°F | 65°F 1984 | -4°F 1961 | 43% | 29% |
| Dec 29 | 36°F | 20°F | 62°F 1984 | -7°F 1961 | 43% | 30% |
| Dec 30 | 36°F | 20°F | 63°F 1971 | -9°F 1983 | 43% | 30% |
| Dec 31 | 35°F | 20°F | 61°F 1951 | -10°F 1976 | 43% | 30% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EST).
- December 1
- sunrise 7:35 AM, sunset 5:03 PM
- December 31
- sunrise 7:54 AM, sunset 5:13 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00334874 (Mansfield 5 W), public domain. Records: NOAA GHCN-Daily, station USW00014891, 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.