Ontario, CA Weather & Growing Conditions
This Afternoon
74°F
Sunny
Sunny, with a high near 74. West wind 0 to 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 74°F | Sunny | 0 to 5 mph W | 0% |
| Tonight | 54°F | Mostly Clear | 0 to 5 mph N | 0% |
| Thursday | 78°F | Mostly Sunny | 0 to 5 mph NW | 0% |
| Thursday Night | 55°F | Partly Cloudy | 0 to 10 mph N | 0% |
| Friday | 81°F | Sunny | 0 to 5 mph NE | 0% |
| Friday Night | 57°F | Clear | 5 to 20 mph NE | 0% |
| Saturday | 83°F | Sunny | 0 to 15 mph NE | 0% |
| Saturday Night | 58°F | Clear | 0 to 20 mph N | 0% |
| Sunday | 84°F | Sunny | 0 to 5 mph E | 0% |
| Sunday Night | 59°F | Mostly Clear | 0 to 10 mph NW | 0% |
| Monday | 82°F | Mostly Sunny | 0 to 5 mph SE | 0% |
| Monday Night | 59°F | Partly Cloudy | 0 to 5 mph N | 0% |
| Tuesday | 81°F | Sunny | 0 mph | 0% |
| Tuesday Night | 58°F | Mostly Clear | 0 mph | 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 (1.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.