Ontario, WI Weather & Growing Conditions
Today
63°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy, with a high near 63. East wind around 7 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 63°F | Showers And Thunderstorms | 7 mph E | 93% |
| Tonight | 53°F | Showers And Thunderstorms Likely | 6 to 9 mph NE | 60% |
| Sunday | 66°F | Slight Chance Rain Showers then Mostly Cloudy | 8 to 13 mph NE | 17% |
| Sunday Night | 47°F | Mostly Cloudy | 12 mph NE | 4% |
| Monday | 63°F | Mostly Cloudy | 10 mph NE | 11% |
| Monday Night | 43°F | Mostly Cloudy | 5 to 8 mph NE | 11% |
| Tuesday | 62°F | Mostly Sunny | 5 to 9 mph E | 7% |
| Tuesday Night | 41°F | Mostly Clear | 1 to 5 mph NE | 2% |
| Wednesday | 66°F | Sunny | 1 to 6 mph E | 2% |
| Wednesday Night | 44°F | Mostly Clear | 0 to 3 mph NE | 2% |
| Thursday | 67°F | Mostly Sunny | 0 to 3 mph NE | 5% |
| Thursday Night | 46°F | Partly Cloudy | 1 mph NE | 4% |
| Friday | 71°F | Mostly Sunny | 0 to 3 mph E | 3% |
| Friday Night | 47°F | Partly Cloudy | 1 mph NE | 3% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Ontario, WI
Last spring frost
Apr 27
First fall frost
Oct 14
Growing season
170 days
Hardiness zone
4b
Explore more for Ontario, WI: full frost dates · planting calendar · Wisconsin frost dates
Climate data from the nearest NOAA station, Cashton, Wi (10.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.