Ontario, CA Weather & Growing Conditions
This Afternoon
86°F
Sunny
Sunny, with a high near 86. West wind 5 to 10 mph, with gusts as high as 20 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 86°F | Sunny | 5 to 10 mph W | 0% |
| Tonight | 64°F | Partly Cloudy | 5 to 10 mph W | 0% |
| Sunday | 84°F | Mostly Sunny | 0 to 10 mph SW | 0% |
| Sunday Night | 63°F | Partly Cloudy | 5 to 10 mph SW | 3% |
| Monday | 79°F | Mostly Sunny | 0 to 10 mph SW | 3% |
| Monday Night | 62°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Tuesday | 82°F | Sunny | 0 to 10 mph SW | 0% |
| Tuesday Night | 64°F | Clear | 0 to 10 mph W | 0% |
| Wednesday | 90°F | Sunny | 0 to 10 mph NW | 0% |
| Wednesday Night | 67°F | Mostly Clear | 0 to 10 mph NW | 0% |
| Thursday | 92°F | Sunny | 0 to 10 mph W | 1% |
| Thursday Night | 68°F | Mostly Clear | 0 to 10 mph W | 1% |
| Friday | 90°F | Sunny | 0 to 5 mph W | 2% |
| Friday Night | 68°F | Mostly Clear | 0 to 5 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Ontario, CA
Last spring frost
Jan 4
First fall frost
Dec 30
Growing season
365 days
Hardiness zone
10a
Explore more for Ontario, CA: full frost dates · planting calendar · California frost dates
Climate data from the nearest NOAA station, Ontario Intl Ap, Ca (4 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.