Ontario, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Ontario, a village in Vernon County, Wisconsin.
Today
61°F
Chance Rain Showers then Mostly Cloudy
A chance of rain showers before noon. Mostly cloudy. High near 61, with temperatures falling to around 54 in the afternoon. Southwest wind around 13 mph, with gusts as high as 24 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Ontario
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 61°F | Chance Rain Showers then Mostly Cloudy | 13 mph SW | 27% |
| Tonight | 43°F | Rain Showers Likely | 6 to 12 mph W | 68% |
| Thursday | 55°F | Rain Showers Likely | 8 to 14 mph NW | 58% |
| Thursday Night | 33°F | Mostly Cloudy | 3 to 10 mph N | 6% |
| Friday | 49°F | Partly Sunny | 2 to 6 mph N | 0% |
| Friday Night | 26°F | Mostly Clear | 1 mph N | 0% |
| Saturday | 52°F | Sunny | 0 to 3 mph W | 0% |
| Saturday Night | 31°F | Mostly Clear | 2 mph W | 4% |
| Sunday | 57°F | Sunny | 2 to 9 mph W | 6% |
| Sunday Night | 32°F | Mostly Clear | 2 mph W | 0% |
| Monday | 62°F | Mostly Sunny | 0 to 10 mph SW | 0% |
| Monday Night | 37°F | Partly Cloudy | 1 to 5 mph W | 0% |
| Tuesday | 61°F | Sunny | 1 to 5 mph NW | 0% |
| Tuesday Night | 35°F | Partly Cloudy | 1 mph NW | 3% |
Forecast source: National Weather Service (api.weather.gov) for Ontario (43.722, -90.593). Updated through the day.
Growing snapshot for Ontario
Last spring frost
Apr 27
First fall frost
Oct 14
Growing season
170 days
Hardiness zone
4b
More local growing data for Ontario: nearby ZIP 54651 weather · frost dates · planting calendar · Wisconsin frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Cashton, Wi (10.7 mi from Ontario). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.