Ontario, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Ontario, a village in Vernon County, Wisconsin.
Today
80°F
Mostly Cloudy then Isolated Rain Showers
Isolated rain showers after 4pm. Mostly cloudy. High near 80, with temperatures falling to around 76 in the afternoon. West wind 5 to 9 mph. Chance of precipitation is 20%.
7-day forecast for Ontario
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 80°F | Mostly Cloudy then Isolated Rain Showers | 5 to 9 mph W | 23% |
| Tonight | 59°F | Scattered Showers And Thunderstorms | 0 to 3 mph W | 38% |
| Wednesday | 79°F | Partly Sunny | 0 to 3 mph NW | 7% |
| Wednesday Night | 53°F | Partly Cloudy | 0 to 3 mph S | 1% |
| Thursday | 83°F | Sunny | 0 to 3 mph S | 1% |
| Thursday Night | 57°F | Mostly Clear | 0 to 3 mph S | 0% |
| Friday | 85°F | Sunny | 0 to 8 mph S | 4% |
| Friday Night | 62°F | Mostly Clear | 1 to 7 mph SW | 13% |
| Saturday | 86°F | Mostly Sunny | 2 to 7 mph SW | 13% |
| Saturday Night | 65°F | Partly Cloudy then Chance Rain Showers | 2 to 6 mph SW | 34% |
| Sunday | 87°F | Chance Rain Showers | 2 to 8 mph W | 34% |
| Sunday Night | 64°F | Chance Showers And Thunderstorms | 0 to 6 mph S | 43% |
| Monday | 85°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 1 to 5 mph S | 43% |
| Monday Night | 63°F | Chance Showers And Thunderstorms | 0 to 3 mph N | 30% |
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 Aug 4, 2026.