Weather on September 23
Rancho Cucamonga, CA
55 Years of Data
Avg High
90°F
Avg Low
61°F
Warmest
1978
87°F avg
Coldest
2007
63°F avg
About This Date
September 23rd in Rancho Cucamonga, CA typically brings hot fall weather, with average highs around 90°F and lows near 61°F — a 29°F daily swing. Over 41 years of records, the warmest September 23rd was in 1978 (87°F average), while the coldest was 2007 (63°F) — a 24°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 1.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.8°F warmer on this date compared to 20-30 years ago.
Planning for September 23rd in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 98° | 69° | 84° | — | — |
| 2024 | 95° | 60° | 78° | — | — |
| 2023 | 83° | 60° | 71° | — | — |
| 2022 | 96° | 65° | 80° | — | — |
| 2021 | 93° | 68° | 81° | — | — |
| 2020 | 93° | 65° | 79° | — | — |
| 2019 | 89° | 65° | 77° | — | — |
| 2018 | 89° | 63° | 76° | — | — |
| 2017 | 77° | 54° | 65° | — | — |
| 2016 | 84° | 55° | 70° | — | — |
| 2015 | 94° | 66° | 80° | — | — |
| 2014 | 97° | 65° | 81° | — | — |
| 2013 | 94° | 57° | 75° | — | — |
| 2012 | 101° | 71° | 86° | — | — |
| 2011 | 90° | 62° | 76° | — | — |
| 2010 | 88° | 54° | 71° | — | — |
| 2009 | 103° | 67° | 85° | — | — |
| 2008 | 93° | 60° | 77° | — | — |
| 2007coldest | 71° | 56° | 63° | — | — |
| 2006 | 87° | 55° | 71° | — | — |
| 2005 | 85° | 60° | 72° | — | — |
| 2004 | 94° | 60° | 77° | — | — |
| 2003 | 98° | 62° | 80° | — | — |
| 2002 | 107° | 67° | 87° | — | — |
| 2001 | 90° | 59° | 74° | — | — |
| 2000 | 74° | 60° | 67° | — | — |
| 1999 | 83° | 61° | 72° | — | — |
| 1998 | 74° | 56° | 65° | — | — |
| 1983 | 85° | 67° | 76° | — | — |
| 1982 | 106° | 62° | 84° | — | — |
| 1981 | 84° | 60° | 72° | — | — |
| 1980 | 87° | 51° | 69° | — | — |
| 1979 | 95° | 62° | 79° | — | — |
| 1978warmest | 105° | 68° | 87° | — | — |
| 1977 | 77° | 51° | 64° | — | — |
| 1976 | 78° | 57° | 68° | — | — |
| 1975 | 98° | 61° | 79° | — | — |
| 1974 | 95° | 65° | 80° | — | — |
| 1973 | 74° | 55° | 64° | — | — |
| 1972 | 83° | 53° | 68° | — | — |
| 1971 | 92° | 53° | 72° | — | — |
41 years of data from ONTARIO INTL AP