Weather on December 31
Ontario, CA
55 Years of Data
About This Date
December 31st in Ontario, CA typically brings mild winter weather, with average highs around 63°F and lows near 42°F. Over 40 years of records, the warmest December 31st was in 1980 (61°F average), while the coldest was 2010 (42°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 18% of December 31st dates historically, with the wettest December 31st recording 1.6" of rain. The last decade has been 2.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.5°F warmer on this date compared to 20-30 years ago.
Planning for December 31st in Ontario, CA? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 64° | 53° | 59° | 0.76" | — |
| 2024 | 66° | 44° | 55° | — | — |
| 2023 | 59° | 49° | 54° | — | — |
| 2022 | 57° | 53° | 55° | — | — |
| 2021 | 60° | 43° | 51° | — | — |
| 2020 | 66° | 38° | 52° | — | — |
| 2019 | 71° | 45° | 58° | — | — |
| 2018 | 60° | 44° | 52° | — | — |
| 2017 | 71° | 47° | 59° | — | — |
| 2016 | 54° | 44° | 49° | 0.41" | — |
| 2015 | 64° | 34° | 49° | — | — |
| 2014 | 52° | 32° | 42° | — | — |
| 2013 | 73° | 42° | 58° | — | — |
| 2012 | 57° | 33° | 45° | — | — |
| 2011 | 79° | 43° | 61° | — | — |
| 2010coldest | 53° | 30° | 42° | — | — |
| 2009 | 66° | 40° | 53° | 0.03" | — |
| 2008 | 70° | 45° | 57° | — | — |
| 2007 | 74° | 38° | 56° | — | — |
| 2006 | 63° | 37° | 50° | — | — |
| 2005 | 56° | 46° | 51° | 1.52" | — |
| 2004 | 54° | 41° | 47° | 1.6" | — |
| 2003 | 64° | 38° | 51° | — | — |
| 2002 | 59° | 42° | 51° | — | — |
| 2001 | 59° | 50° | 55° | — | — |
| 2000 | 76° | 39° | 57° | — | — |
| 1999 | 53° | 46° | 50° | 0.66" | — |
| 1998 | 63° | 44° | 53° | — | — |
| 1983 | 73° | 44° | 59° | — | — |
| 1981 | 54° | 48° | 51° | — | — |
| 1980warmest | 78° | 44° | 61° | — | — |
| 1979 | 70° | 48° | 59° | — | — |
| 1978 | 62° | 38° | 50° | — | — |
| 1977 | 55° | 45° | 50° | — | — |
| 1976 | 58° | 44° | 51° | 0.23" | — |
| 1975 | 58° | 38° | 48° | — | — |
| 1974 | 52° | 41° | 46° | — | — |
| 1973 | 61° | 39° | 50° | — | — |
| 1972 | 58° | 33° | 45° | — | — |
| 1971 | 61° | 36° | 48° | — | — |
Ontario, CA Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Ontario, CA Monthly Precipitation
Average rainfall per month, in inches.
Ontario, CA Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Ontario, CA
Ontario, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.