Weather on May 17
Ontario, CA
55 Years of Data
Avg High
79°F
Avg Low
53°F
Warmest
2008
83°F avg
Coldest
1977
53°F avg
About This Date
May 17th in Ontario, CA typically brings pleasant spring weather, with average highs around 79°F and lows near 53°F — a 26°F daily swing. Over 41 years of records, the warmest May 17th was in 2008 (83°F average), while the coldest was 1977 (53°F) — a 30°F range across recorded history. Rain or other precipitation has occurred on about 7% of May 17th dates historically. The last decade has been 2.6°F cooler on this date compared to 20-30 years ago.
The last decade has been 2.6°F cooler on this date compared to 20-30 years ago.
Planning for May 17th in Ontario, CA? Great weather for outdoor activities.
Warming Trend
0.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 65° | 56° | 60° | 0.03" | — |
| 2024 | 71° | 55° | 63° | — | — |
| 2023 | 85° | 56° | 70° | — | — |
| 2022 | 78° | 56° | 67° | — | — |
| 2021 | 66° | 55° | 61° | — | — |
| 2020 | 84° | 60° | 72° | — | — |
| 2019 | 76° | 55° | 65° | — | — |
| 2018 | 76° | 53° | 64° | — | — |
| 2017 | 62° | 52° | 57° | — | — |
| 2016 | 78° | 59° | 69° | — | — |
| 2015 | 74° | 53° | 63° | — | — |
| 2014 | 91° | 64° | 78° | — | — |
| 2013 | 72° | 60° | 66° | — | — |
| 2012 | 87° | 59° | 73° | — | — |
| 2011 | 65° | 50° | 57° | 0.1" | — |
| 2010 | 65° | 54° | 59° | 0.08" | — |
| 2009 | 93° | 62° | 78° | — | — |
| 2008warmest | 102° | 65° | 83° | — | — |
| 2007 | 81° | 55° | 68° | — | — |
| 2006 | 88° | 45° | 66° | — | — |
| 2005 | 75° | 55° | 65° | — | — |
| 2004 | 76° | 58° | 67° | — | — |
| 2003 | 81° | 59° | 70° | — | — |
| 2002 | 81° | 55° | 68° | — | — |
| 2001 | 86° | 56° | 71° | — | — |
| 2000 | 75° | 48° | 62° | — | — |
| 1999 | 87° | 52° | 69° | — | — |
| 1984 | 86° | 47° | 66° | — | — |
| 1983 | 84° | 50° | 67° | — | — |
| 1982 | 90° | 52° | 71° | — | — |
| 1981 | 83° | 42° | 62° | — | — |
| 1980 | 80° | 49° | 64° | — | — |
| 1979 | 80° | 51° | 66° | — | — |
| 1978 | 85° | 50° | 67° | — | — |
| 1977coldest | 67° | 40° | 53° | — | — |
| 1976 | 85° | 45° | 65° | — | — |
| 1975 | 80° | 46° | 63° | — | — |
| 1974 | 66° | 49° | 57° | — | — |
| 1973 | 82° | 52° | 67° | — | — |
| 1972 | 73° | 54° | 63° | — | — |
| 1971 | 81° | 47° | 64° | — | — |
41 years of data from ONTARIO INTL AP