Ontario, WI Weather & Growing Conditions
Today
56°F
Chance Rain Showers
A chance of rain showers. Cloudy. High near 56, with temperatures falling to around 50 in the afternoon. Southwest wind around 13 mph, with gusts as high as 24 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 56°F | Chance Rain Showers | 13 mph SW | 50% |
| Tonight | 43°F | Rain Showers | 8 to 13 mph SW | 83% |
| Thursday | 48°F | Rain Showers Likely | 8 to 14 mph NW | 69% |
| Thursday Night | 34°F | Mostly Cloudy | 6 to 13 mph N | 6% |
| Friday | 48°F | Partly Sunny | 2 to 7 mph N | 0% |
| Friday Night | 26°F | Mostly Clear | 1 mph N | 0% |
| Saturday | 51°F | Sunny | 0 to 5 mph W | 0% |
| Saturday Night | 32°F | Mostly Clear | 2 mph W | 4% |
| Sunday | 55°F | Sunny | 2 to 9 mph W | 6% |
| Sunday Night | 33°F | Mostly Clear | 2 mph W | 0% |
| Monday | 61°F | Mostly Sunny | 1 to 10 mph SW | 0% |
| Monday Night | 37°F | Partly Cloudy | 1 to 6 mph W | 0% |
| Tuesday | 60°F | Sunny | 1 to 5 mph NW | 0% |
| Tuesday Night | 36°F | Partly Cloudy | 1 mph NW | 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 Nov 4, 2026.