Weather on September 17
Rancho Cucamonga, CA
55 Years of Data
Avg High
87°F
Avg Low
60°F
Warmest
2014
87°F avg
Coldest
1977
62°F avg
About This Date
September 17th in Rancho Cucamonga, CA typically brings warm fall weather, with average highs around 87°F and lows near 60°F — a 27°F daily swing. Over 41 years of records, the warmest September 17th was in 2014 (87°F average), while the coldest was 1977 (62°F) — a 25°F range across recorded history. This date has historically been dry, with little recorded precipitation. 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 September 17th in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 97° | 70° | 83° | — | — |
| 2024 | 76° | 55° | 65° | — | — |
| 2023 | 74° | 64° | 69° | — | — |
| 2022 | 81° | 61° | 71° | — | — |
| 2021 | 86° | 59° | 73° | — | — |
| 2020 | 102° | 63° | 82° | — | — |
| 2019 | 87° | 62° | 75° | — | — |
| 2018 | 94° | 61° | 77° | — | — |
| 2017 | 78° | 63° | 70° | — | — |
| 2016 | 94° | 57° | 75° | — | — |
| 2015 | 83° | 62° | 72° | — | — |
| 2014warmest | 100° | 74° | 87° | — | — |
| 2013 | 89° | 62° | 76° | — | — |
| 2012 | 91° | 63° | 77° | — | — |
| 2011 | 79° | 60° | 69° | — | — |
| 2010 | 87° | 55° | 71° | — | — |
| 2009 | 97° | 65° | 81° | — | — |
| 2008 | 92° | 64° | 78° | — | — |
| 2007 | 77° | 57° | 67° | — | — |
| 2006 | 96° | 55° | 76° | — | — |
| 2005 | 81° | 55° | 68° | — | — |
| 2004 | 88° | 61° | 74° | — | — |
| 2003 | 86° | 57° | 72° | — | — |
| 2002 | 87° | 59° | 73° | — | — |
| 2001 | 84° | 57° | 71° | — | — |
| 2000 | 102° | 68° | 85° | — | — |
| 1999 | 80° | 57° | 69° | — | — |
| 1998 | 90° | 58° | 74° | — | — |
| 1983 | 96° | 61° | 78° | — | — |
| 1982 | 73° | 52° | 62° | — | — |
| 1981 | 102° | 64° | 83° | — | — |
| 1980 | 102° | 65° | 83° | — | — |
| 1979 | 94° | 64° | 79° | — | — |
| 1978 | 75° | 59° | 67° | — | — |
| 1977coldest | 75° | 48° | 62° | — | — |
| 1976 | 75° | 56° | 65° | — | — |
| 1975 | 92° | 65° | 78° | — | — |
| 1974 | 88° | 54° | 71° | — | — |
| 1973 | 81° | 46° | 63° | — | — |
| 1972 | 82° | 50° | 66° | — | — |
| 1971 | 75° | 63° | 69° | — | — |
41 years of data from ONTARIO INTL AP