Weather on December 9
Ontario, CA
55 Years of Data
Avg High
68°F
Avg Low
43°F
Warmest
2015
66°F avg
Coldest
1972
37°F avg
About This Date
December 9th in Ontario, CA typically brings mild winter weather, with average highs around 68°F and lows near 43°F — a 25°F daily swing. Over 41 years of records, the warmest December 9th was in 2015 (66°F average), while the coldest was 1972 (37°F) — a 29°F range across recorded history. Rain or other precipitation has occurred on about 12% of December 9th dates historically, with the wettest December 9th recording 0.74" of rain. The last decade has been 2.7°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.7°F warmer on this date compared to 20-30 years ago.
Planning for December 9th in Ontario, CA? Great weather for outdoor activities.
Warming Trend
1.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 81° | 49° | 65° | — | — |
| 2024 | 75° | 44° | 60° | — | — |
| 2023 | 72° | 43° | 57° | — | — |
| 2022 | 61° | 39° | 50° | — | — |
| 2021 | 55° | 49° | 52° | 0.56" | — |
| 2020 | 76° | 47° | 61° | — | — |
| 2019 | 67° | 49° | 58° | — | — |
| 2018 | 72° | 45° | 58° | — | — |
| 2017 | 84° | 48° | 66° | — | — |
| 2016 | 64° | 45° | 54° | — | — |
| 2015warmest | 78° | 53° | 66° | — | — |
| 2014 | 77° | 50° | 64° | — | — |
| 2013 | 60° | 35° | 48° | — | — |
| 2012 | 70° | 46° | 58° | — | — |
| 2011 | 71° | 37° | 54° | — | — |
| 2010 | 71° | 45° | 58° | — | — |
| 2009 | 58° | 37° | 47° | — | — |
| 2008 | 70° | 45° | 57° | — | — |
| 2007 | 60° | 45° | 52° | 0.2" | — |
| 2006 | 66° | 49° | 57° | 0.74" | — |
| 2005 | 72° | 48° | 60° | 0.15" | — |
| 2004 | 66° | 50° | 58° | — | — |
| 2003 | 69° | 39° | 54° | — | — |
| 2002 | 69° | 48° | 59° | — | — |
| 2001 | 63° | 38° | 50° | — | — |
| 2000 | 63° | 53° | 58° | — | — |
| 1999 | 66° | 41° | 54° | — | — |
| 1998 | 61° | 39° | 50° | — | — |
| 1983 | 59° | 40° | 49° | 0.25" | — |
| 1982 | 62° | 42° | 52° | — | — |
| 1981 | 77° | 46° | 62° | — | — |
| 1980 | 64° | 37° | 51° | — | — |
| 1979 | 77° | 47° | 62° | — | — |
| 1978 | 58° | 29° | 43° | — | — |
| 1977 | 70° | 42° | 56° | — | — |
| 1976 | 63° | 40° | 51° | — | — |
| 1975 | 81° | 50° | 65° | — | — |
| 1974 | 64° | 37° | 51° | — | — |
| 1973 | 78° | 48° | 63° | — | — |
| 1972coldest | 45° | 30° | 37° | — | — |
| 1971 | 56° | 30° | 43° | — | — |
41 years of data from ONTARIO INTL AP