Weather on September 12
Rancho Cucamonga, CA
55 Years of Data
Avg High
89°F
Avg Low
62°F
Warmest
1971
91°F avg
Coldest
1972
64°F avg
About This Date
September 12th in Rancho Cucamonga, CA typically brings warm fall weather, with average highs around 89°F and lows near 62°F — a 27°F daily swing. Over 41 years of records, the warmest September 12th was in 1971 (91°F average), while the coldest was 1972 (64°F) — a 27°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
Planning for September 12th in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 81° | 61° | 71° | — | — |
| 2024 | 82° | 59° | 71° | — | — |
| 2023 | 89° | 65° | 77° | — | — |
| 2022 | 88° | 71° | 79° | — | — |
| 2021 | 101° | 71° | 86° | — | — |
| 2020 | 94° | 64° | 79° | — | — |
| 2019 | 98° | 64° | 81° | — | — |
| 2018 | 89° | 62° | 76° | — | — |
| 2017 | 93° | 68° | 81° | — | — |
| 2016 | 80° | 60° | 70° | — | — |
| 2015 | 91° | 75° | 83° | — | — |
| 2014 | 102° | 70° | 86° | — | — |
| 2013 | 94° | 63° | 78° | — | — |
| 2012 | 92° | 70° | 81° | — | — |
| 2011 | 92° | 58° | 75° | — | — |
| 2010 | 91° | 58° | 74° | — | — |
| 2009 | 90° | 63° | 76° | — | — |
| 2008 | 76° | 62° | 69° | — | — |
| 2007 | 96° | 66° | 81° | — | — |
| 2006 | 91° | 66° | 79° | — | — |
| 2005 | 78° | 55° | 67° | — | — |
| 2004 | 94° | 67° | 80° | — | — |
| 2003 | 89° | 61° | 75° | — | — |
| 2002 | 92° | 63° | 77° | — | — |
| 2001 | 87° | 60° | 74° | — | — |
| 2000 | 105° | 66° | 86° | — | — |
| 1999 | 92° | 59° | 75° | — | — |
| 1998 | 89° | 57° | 73° | — | — |
| 1983 | 99° | 66° | 82° | — | — |
| 1982 | 80° | 58° | 69° | — | — |
| 1981 | 94° | 56° | 75° | — | — |
| 1980 | 82° | 56° | 69° | — | — |
| 1979 | 98° | 65° | 81° | — | — |
| 1978 | 77° | 55° | 66° | — | — |
| 1977 | 84° | 54° | 69° | — | — |
| 1976 | 74° | 60° | 67° | — | — |
| 1975 | 77° | 51° | 64° | — | — |
| 1974 | 82° | 58° | 70° | — | — |
| 1973 | 79° | 51° | 65° | — | — |
| 1972coldest | 82° | 47° | 64° | — | — |
| 1971warmest | 110° | 72° | 91° | — | — |
41 years of data from ONTARIO INTL AP