Weather on December 18
Rancho Cucamonga, CA
55 Years of Data
Avg High
67°F
Avg Low
43°F
Warmest
2024
68°F avg
Coldest
1978
46°F avg
About This Date
December 18th in Rancho Cucamonga, CA typically brings mild winter weather, with average highs around 67°F and lows near 43°F. Over 41 years of records, the warmest December 18th was in 2024 (68°F average), while the coldest was 1978 (46°F) — a 22°F range across recorded history. Rain or other precipitation has occurred on about 17% of December 18th dates historically, with the wettest December 18th recording 3.45" of rain. Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for December 18th in Rancho Cucamonga, CA? Great weather for outdoor activities.
Warming Trend
0.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 82° | 49° | 65° | — | — |
| 2024warmest | 85° | 51° | 68° | — | — |
| 2023 | 71° | 54° | 62° | 0.13" | — |
| 2022 | 62° | 35° | 49° | — | — |
| 2021 | 67° | 38° | 52° | — | — |
| 2020 | 68° | 45° | 56° | — | — |
| 2019 | 63° | 43° | 53° | — | — |
| 2018 | 68° | 53° | 61° | — | — |
| 2017 | 70° | 38° | 54° | — | — |
| 2016 | 65° | 33° | 49° | — | — |
| 2015 | 73° | 39° | 56° | — | — |
| 2014 | 62° | 48° | 55° | — | — |
| 2013 | 72° | 54° | 63° | — | — |
| 2012 | 59° | 43° | 51° | 0.46" | — |
| 2011 | 59° | 40° | 49° | — | — |
| 2010 | 59° | 54° | 56° | 1.22" | — |
| 2009 | 78° | 45° | 61° | — | — |
| 2008 | 54° | 38° | 46° | 0.1" | — |
| 2007 | 57° | 48° | 53° | 0.53" | — |
| 2006 | 58° | 36° | 47° | — | — |
| 2005 | 61° | 47° | 54° | — | — |
| 2004 | 80° | 42° | 61° | — | — |
| 2003 | 81° | 46° | 63° | — | — |
| 2002 | 57° | 39° | 48° | — | — |
| 2001 | 69° | 39° | 54° | — | — |
| 2000 | 75° | 46° | 61° | — | — |
| 1999 | 75° | 45° | 60° | — | — |
| 1998 | 60° | 49° | 54° | — | — |
| 1983 | 63° | 41° | 52° | — | — |
| 1982 | 76° | 39° | 57° | — | — |
| 1981 | 73° | 42° | 58° | — | — |
| 1980 | 69° | 40° | 54° | — | — |
| 1979 | 79° | 49° | 64° | — | — |
| 1978coldest | 50° | 42° | 46° | 3.45" | — |
| 1977 | 59° | 48° | 54° | 1.93" | — |
| 1976 | 65° | 42° | 53° | — | — |
| 1975 | 68° | 39° | 54° | — | — |
| 1974 | 70° | 41° | 55° | — | — |
| 1973 | 67° | 38° | 52° | — | — |
| 1972 | 72° | 42° | 57° | — | — |
| 1971 | 63° | 41° | 52° | — | — |
41 years of data from ONTARIO INTL AP