Weather on September 4
Rancho Cucamonga, CA
55 Years of Data
Avg High
95°F
Avg Low
65°F
Warmest
2022
94°F avg
Coldest
1973
64°F avg
About This Date
September 4th in Rancho Cucamonga, CA typically brings hot fall weather, with average highs around 95°F and lows near 65°F — a 30°F daily swing. Over 41 years of records, the warmest September 4th was in 2022 (94°F average), while the coldest was 1973 (64°F) — a 30°F range across recorded history. Rain or other precipitation has occurred on about 5% of September 4th dates historically, with the wettest September 4th recording 1.57" of rain. The last decade has been 5.0°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.0°F warmer on this date compared to 20-30 years ago.
Planning for September 4th in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 97° | 71° | 84° | — | — |
| 2024 | 106° | 72° | 89° | — | — |
| 2023 | 81° | 63° | 72° | — | — |
| 2022warmest | 109° | 79° | 94° | — | — |
| 2021 | 102° | 65° | 83° | — | — |
| 2020 | 103° | 69° | 86° | — | — |
| 2019 | 102° | 75° | 89° | — | — |
| 2018 | 88° | 65° | 76° | — | — |
| 2017 | 90° | 71° | 80° | — | — |
| 2016 | 80° | 61° | 70° | — | — |
| 2015 | 83° | 62° | 72° | — | — |
| 2014 | 88° | 66° | 77° | — | — |
| 2013 | 104° | 74° | 89° | — | — |
| 2012 | 99° | 69° | 84° | — | — |
| 2011 | 92° | 61° | 76° | — | — |
| 2010 | 107° | 65° | 86° | — | — |
| 2009 | 101° | 74° | 87° | — | — |
| 2008 | 99° | 69° | 84° | — | — |
| 2007 | 101° | 71° | 86° | — | — |
| 2006 | 103° | 70° | 86° | — | — |
| 2005 | 93° | 59° | 76° | — | — |
| 2004 | 96° | 59° | 78° | — | — |
| 2003 | 102° | 68° | 85° | — | — |
| 2002 | 98° | 66° | 82° | — | — |
| 2001 | 92° | 63° | 77° | — | — |
| 2000 | 87° | 57° | 72° | — | — |
| 1999 | 84° | 57° | 71° | — | — |
| 1998 | 82° | 71° | 77° | — | — |
| 1983 | 95° | 56° | 75° | — | — |
| 1982 | 104° | 66° | 85° | — | — |
| 1981 | 89° | 58° | 73° | — | — |
| 1980 | 92° | 56° | 74° | — | — |
| 1979 | 93° | 55° | 74° | — | — |
| 1978 | 95° | 70° | 82° | — | — |
| 1977 | 98° | 59° | 79° | — | — |
| 1976 | 93° | 63° | 78° | 1.57" | — |
| 1975 | 98° | 63° | 80° | — | — |
| 1974 | 98° | 66° | 82° | — | — |
| 1973coldest | 76° | 52° | 64° | — | — |
| 1972 | 94° | 63° | 78° | 0.13" | — |
| 1971 | 94° | 50° | 72° | — | — |
41 years of data from ONTARIO INTL AP