Weather on September 3
Ontario, CA
55 Years of Data
Avg High
94°F
Avg Low
65°F
Warmest
2007
95°F avg
Coldest
1973
67°F avg
About This Date
September 3rd in Ontario, CA typically brings hot fall weather, with average highs around 94°F and lows near 65°F — a 29°F daily swing. Over 41 years of records, the warmest September 3rd was in 2007 (95°F average), while the coldest was 1973 (67°F) — a 28°F range across recorded history. Rain or other precipitation has occurred on about 5% of September 3rd dates historically. The last decade has been 4.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.5°F warmer on this date compared to 20-30 years ago.
Planning for September 3rd in Ontario, 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 | 99° | 72° | 85° | — | — |
| 2024 | 101° | 69° | 85° | — | — |
| 2023 | 81° | 64° | 72° | 0.03" | — |
| 2022 | 106° | 77° | 91° | — | — |
| 2021 | 94° | 63° | 78° | — | — |
| 2020 | 95° | 65° | 80° | — | — |
| 2019 | 98° | 75° | 87° | — | — |
| 2018 | 87° | 66° | 77° | — | — |
| 2017 | 100° | 73° | 87° | 0.05" | — |
| 2016 | 83° | 63° | 73° | — | — |
| 2015 | 85° | 62° | 73° | — | — |
| 2014 | 91° | 66° | 79° | — | — |
| 2013 | 101° | 75° | 88° | — | — |
| 2012 | 100° | 65° | 82° | — | — |
| 2011 | 93° | 60° | 77° | — | — |
| 2010 | 103° | 65° | 84° | — | — |
| 2009 | 101° | 73° | 87° | — | — |
| 2008 | 101° | 68° | 84° | — | — |
| 2007warmest | 110° | 80° | 95° | — | — |
| 2006 | 104° | 70° | 87° | — | — |
| 2005 | 94° | 60° | 77° | — | — |
| 2004 | 83° | 62° | 72° | — | — |
| 2003 | 94° | 66° | 80° | — | — |
| 2002 | 100° | 71° | 86° | — | — |
| 2001 | 88° | 65° | 76° | — | — |
| 2000 | 83° | 56° | 69° | — | — |
| 1999 | 79° | 59° | 69° | — | — |
| 1998 | 101° | 73° | 87° | — | — |
| 1983 | 99° | 63° | 81° | — | — |
| 1982 | 106° | 69° | 87° | — | — |
| 1981 | 89° | 56° | 72° | — | — |
| 1980 | 92° | 52° | 72° | — | — |
| 1979 | 94° | 62° | 78° | — | — |
| 1978 | 96° | 64° | 80° | — | — |
| 1977 | 92° | 58° | 75° | — | — |
| 1976 | 95° | 67° | 81° | — | — |
| 1975 | 97° | 59° | 78° | — | — |
| 1974 | 95° | 63° | 79° | — | — |
| 1973coldest | 82° | 51° | 67° | — | — |
| 1972 | 83° | 58° | 70° | — | — |
| 1971 | 85° | 57° | 71° | — | — |
41 years of data from ONTARIO INTL AP