Ontario, CA Weather & Growing Conditions
Overnight
67°F
Mostly Clear
Mostly clear, with a low around 67. West wind around 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 67°F | Mostly Clear | 5 mph W | 0% |
| Tuesday | 95°F | Sunny | 0 to 15 mph W | 0% |
| Tuesday Night | 67°F | Mostly Clear | 0 to 15 mph SW | 0% |
| Wednesday | 95°F | Sunny | 0 to 15 mph SW | 0% |
| Wednesday Night | 67°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Thursday | 97°F | Sunny | 0 to 10 mph SW | 1% |
| Thursday Night | 68°F | Mostly Clear | 0 to 10 mph W | 1% |
| Friday | 96°F | Sunny | 0 to 10 mph SW | 0% |
| Friday Night | 69°F | Mostly Clear | 0 to 10 mph W | 0% |
| Saturday | 98°F | Sunny | 0 to 10 mph SW | 0% |
| Saturday Night | 69°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Sunday | 97°F | Sunny | 0 to 15 mph SW | 1% |
| Sunday Night | 68°F | Mostly Clear | 0 to 15 mph SW | 1% |
| Monday | 94°F | Sunny | 0 to 15 mph SW | 2% |
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 Aug 4, 2026.