Weather on October 18
Ontario, CA
55 Years of Data
Avg High
81°F
Avg Low
55°F
Warmest
2003
81°F avg
Coldest
1971
53°F avg
About This Date
October 18th in Ontario, CA typically brings warm fall weather, with average highs around 81°F and lows near 55°F — a 26°F daily swing. Over 41 years of records, the warmest October 18th was in 2003 (81°F average), while the coldest was 1971 (53°F) — a 28°F range across recorded history. Rain or other precipitation has occurred on about 7% of October 18th dates historically, with the wettest October 18th recording 1.45" of rain. The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
Planning for October 18th in Ontario, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 86° | 56° | 71° | — | — |
| 2024 | 77° | 57° | 67° | — | — |
| 2023 | 101° | 60° | 80° | — | — |
| 2022 | 95° | 60° | 78° | — | — |
| 2021 | 67° | 53° | 60° | — | — |
| 2020 | 90° | 62° | 76° | — | — |
| 2019 | 81° | 56° | 68° | — | — |
| 2018 | 88° | 55° | 71° | — | — |
| 2017 | 90° | 66° | 78° | — | — |
| 2016 | 78° | 54° | 66° | — | — |
| 2015 | 80° | 65° | 72° | — | — |
| 2014 | 79° | 61° | 70° | — | — |
| 2013 | 88° | 54° | 71° | — | — |
| 2012 | 80° | 65° | 72° | — | — |
| 2011 | 84° | 57° | 71° | — | — |
| 2010 | 69° | 58° | 63° | 0.03" | — |
| 2009 | 88° | 59° | 73° | — | — |
| 2008 | 86° | 57° | 72° | — | — |
| 2007 | 83° | 51° | 67° | — | — |
| 2006 | 81° | 52° | 66° | — | — |
| 2005 | 63° | 55° | 59° | 1.45" | — |
| 2004 | 68° | 58° | 63° | 0.05" | — |
| 2003warmest | 99° | 63° | 81° | — | — |
| 2002 | 69° | 55° | 62° | — | — |
| 2001 | 86° | 54° | 70° | — | — |
| 2000 | 74° | 58° | 66° | — | — |
| 1999 | 85° | 51° | 68° | — | — |
| 1998 | 84° | 44° | 64° | — | — |
| 1983 | 79° | 49° | 64° | — | — |
| 1982 | 80° | 47° | 63° | — | — |
| 1981 | 87° | 57° | 72° | — | — |
| 1980 | 80° | 43° | 61° | — | — |
| 1979 | 66° | 52° | 59° | — | — |
| 1978 | 82° | 49° | 65° | — | — |
| 1977 | 80° | 49° | 64° | — | — |
| 1976 | 71° | 57° | 64° | — | — |
| 1975 | 74° | 45° | 59° | — | — |
| 1974 | 89° | 58° | 73° | — | — |
| 1973 | 91° | 60° | 76° | — | — |
| 1972 | 63° | 49° | 56° | — | — |
| 1971coldest | 64° | 42° | 53° | — | — |
41 years of data from ONTARIO INTL AP