Ontario, CA All-Time Weather Extremes
The most extreme temperature, precipitation, and snowfall ever recorded in Ontario, from NOAA daily weather observations.
| Temperature | ||
|---|---|---|
| Record High | 120.9°F (49°C) | September 6, 2020 |
| Record Low | 20.1°F (-7°C) | January 14, 2007 |
| Lowest High | 46.9°F (8°C) | January 26, 2001 and December 14, 2001 |
| Highest Low | 78°F (26°C) | October 24, 2017 |
| Highest Mean | 97.4°F (36°C) | September 6, 2020 |
| Lowest Mean | 37°F (3°C) | January 14, 2007 |
| Precipitation | ||
| Max in One Calendar Day | 3.46" (87.9 mm) | February 5, 2024 |
| Max in One Month | 11.00" (279.4 mm) | February 2024 |
| Least in One Month | 0.00" (0.0 mm) | June 2003 |
| Max in One Year | 21.62" (549.1 mm) | 2023 |
| Least in One Year | 2.33" (59.2 mm) | 2013 |
| Period of Record | ||
| Temperature | April 1, 1998 – August 1, 2026 | |
| Precipitation | April 1, 1998 – August 1, 2026 | |
| Snowfall | April 1, 2011 – July 30, 2026 | |
Note: Records compiled from NOAA GHCN-Daily observations at CHINO AP (4 mi from Ontario, CA). Quality-flagged readings are excluded. Monthly and annual totals require substantially complete reporting for “least” records.
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Frequently Asked Questions
What is the hottest temperature ever recorded in Ontario, CA?
The all-time record high in Ontario, CA is 120.9°F (49°C), set on September 6, 2020.
What is the coldest temperature ever recorded in Ontario, CA?
The all-time record low in Ontario, CA is 20.1°F (-7°C), set on January 14, 2007.
What is the most rain Ontario, CA has ever had in one day?
The most precipitation recorded in one calendar day near Ontario, CA is 3.46 inches, on February 5, 2024.
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