Joshua Tree National Park / Public domain
Ontario, CA Weather on May 25
May 25th in Ontario, CA typically brings pleasant spring weather, with average highs around 78°F and lows near 55°F. Over 42 years of records, the warmest May 25th was in 2021 (78°F average), while the coldest was 1980 (54°F) — a 24°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 1.3°F warmer on this date compared to 20-30 years ago.
What to Expect on May 25
Planning for May 25th in Ontario, CA? Great weather for outdoor activities.
May 25 Weather Records for Ontario
- •The all-time record high for May 25th in Ontario, CA is 99°F, set in 1974.
- •The coldest May 25th on record dropped to 39°F in 1980.
- •Temperatures have reached 90°F or higher on May 25th in 4 of the last 42 years.
- •Last year (1971), May 25th was 6°F warmer than the long-term average.
Frequently Asked Questions
What was the warmest May 25 ever in Ontario?
The warmest May 25 in Ontario, CA reached 99°F in 1974. That is 21°F above the long-term average high of 78°F.
What was the coldest May 25 ever in Ontario?
The coldest May 25 in Ontario, CA dropped to 39°F in 1980. That is 16°F below the long-term average low of 55°F.
What is the average temperature on May 25 in Ontario?
On May 25, Ontario averages a high of 78°F and a low of 55°F based on 42 years of NOAA weather observations from ONTARIO INTL AP.
How many years of weather data are available for May 25 in Ontario?
We have 42 years of weather records for May 25 in Ontario, CA, sourced from NOAA's Global Historical Climatology Network. Records include daily high and low temperatures, precipitation, and snowfall data going back to 2025.
May 25 Weather History in Ontario
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 78°F | 58°F | 0" | -- |
| 2024 | 71°F | 54°F | 0" | -- |
| 2023 | 71°F | 56°F | 0" | -- |
| 2022 | 86°F | 57°F | 0" | -- |
| 2021 | 92°F | 64°F | 0" | -- |
| 2020 | 92°F | 56°F | 0" | -- |
| 2019 | 77°F | 55°F | 0" | -- |
| 2018 | 72°F | 55°F | 0" | -- |
| 2017 | 72°F | 56°F | 0" | -- |
| 2016 | 70°F | 54°F | 0" | -- |
| 2015 | 73°F | 53°F | 0" | -- |
| 2014 | 86°F | 60°F | 0" | -- |
| 2013 | 78°F | 56°F | 0" | -- |
| 2012 | 71°F | 53°F | 0" | -- |
| 2011 | 80°F | 54°F | 0" | -- |
| 2010 | 75°F | 48°F | 0" | -- |
| 2009 | 77°F | 58°F | 0" | -- |
| 2008 | 66°F | 49°F | 0" | -- |
| 2007 | 84°F | 57°F | 0" | -- |
| 2006 | 88°F | 60°F | 0" | -- |
| 2005 | 88°F | 58°F | 0" | -- |
| 2004 | 71°F | 57°F | 0" | -- |
| 2003 | 71°F | 56°F | 0" | -- |
| 2002 | 77°F | 53°F | 0" | -- |
| 2001 | 85°F | 60°F | 0" | -- |
| 2000 | 65°F | 58°F | 0" | -- |
| 1999 | 81°F | 54°F | 0" | -- |
| 1998 | 67°F | 58°F | 0" | -- |
| 1984 | 92°F | 54°F | 0" | -- |
| 1983 | 86°F | 57°F | 0" | -- |
| 1982 | 79°F | 59°F | 0" | -- |
| 1981 | 82°F | 59°F | 0" | -- |
| 1980 | 69°F | 39°F | 0" | -- |
| 1979 | 83°F | 55°F | 0" | -- |
| 1978 | 72°F | 42°F | 0" | -- |
| 1977 | 66°F | 48°F | 0" | -- |
| 1976 | 71°F | 54°F | 0" | -- |
| 1975 | 80°F | 49°F | 0" | -- |
| 1974 | 99°F | 55°F | 0" | -- |
| 1973 | 70°F | 48°F | 0" | -- |
| 1972 | 69°F | 52°F | 0" | -- |
| 1971 | 84°F | 52°F | 0" | -- |
Based on 42 years of data from NOAA station: ONTARIO INTL AP
Monthly Climate Averages
Historical temperature and precipitation averages for Ontario, CA, based on 55+ years of weather data.
Temperatures in Fahrenheit. Precipitation and snowfall in inches.