Weather on December 21
Rancho Cucamonga, CA
55 Years of Data
Avg High
65°F
Avg Low
44°F
Warmest
2005
66°F avg
Coldest
1998
43°F avg
About This Date
December 21st in Rancho Cucamonga, CA typically brings mild winter weather, with average highs around 65°F and lows near 44°F. Over 41 years of records, the warmest December 21st was in 2005 (66°F average), while the coldest was 1998 (43°F) — a 23°F range across recorded history. Rain or other precipitation has occurred on about 22% of December 21st dates historically, with the wettest December 21st recording 7.21" of rain. The last decade has been 4.0°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.0°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in Rancho Cucamonga, CA? Great weather for outdoor activities.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 75° | 47° | 61° | — | — |
| 2024 | 72° | 45° | 58° | — | — |
| 2023 | 68° | 55° | 62° | — | — |
| 2022 | 72° | 40° | 56° | — | — |
| 2021 | 67° | 47° | 57° | — | — |
| 2020 | 82° | 46° | 64° | — | — |
| 2019 | 73° | 47° | 60° | — | — |
| 2018 | 71° | 51° | 61° | — | — |
| 2017 | 60° | 44° | 52° | — | — |
| 2016 | 62° | 49° | 55° | 0.66" | — |
| 2015 | 59° | 41° | 50° | 0.05" | — |
| 2014 | 65° | 44° | 54° | — | — |
| 2013 | 59° | 40° | 49° | — | — |
| 2012 | 65° | 33° | 49° | — | — |
| 2011 | 62° | 39° | 51° | — | — |
| 2010 | 55° | 50° | 53° | 7.21" | — |
| 2009 | 63° | 48° | 55° | — | — |
| 2008 | 64° | 37° | 51° | — | — |
| 2007 | 58° | 44° | 51° | 0.08" | — |
| 2006 | 62° | 36° | 49° | — | — |
| 2005warmest | 82° | 50° | 66° | — | — |
| 2004 | 65° | 48° | 56° | — | — |
| 2003 | 64° | 47° | 55° | — | — |
| 2002 | 55° | 46° | 51° | 0.08" | — |
| 2001 | 52° | 44° | 48° | 0.61" | — |
| 2000 | 74° | 42° | 58° | — | — |
| 1999 | 74° | 47° | 60° | — | — |
| 1998coldest | 52° | 34° | 43° | — | — |
| 1983 | 57° | 47° | 52° | — | — |
| 1982 | 66° | 36° | 51° | — | — |
| 1981 | 65° | 50° | 57° | 0.1" | — |
| 1980 | 78° | 42° | 60° | — | — |
| 1979 | 57° | 48° | 53° | 0.38" | — |
| 1978 | 63° | 34° | 48° | — | — |
| 1977 | 63° | 48° | 55° | 0.05" | — |
| 1976 | 68° | 40° | 54° | — | — |
| 1975 | 63° | 39° | 51° | — | — |
| 1974 | 70° | 43° | 56° | — | — |
| 1973 | 63° | 41° | 52° | — | — |
| 1972 | 76° | 47° | 61° | — | — |
| 1971 | 61° | 37° | 49° | — | — |
41 years of data from ONTARIO INTL AP