National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Sparta, Sparta / Fort McCoy Airport (KCMY)

Lat: 43.96°NLon: 90.74°WElev: 837ft.

Fair

19°F

-7°C

Humidity 93%
Wind Speed Calm
Barometer 30.21 in (1024.5 mb)
Dewpoint 17°F (-8°C)
Visibility 10.00 mi
Last update 13 Nov 10:55 pm CST
Extended Forecast for

Ontario WI

  • Tonight

    Tonight: Clear, with a low around 21. Calm wind.

    Low: 21 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 46. Calm wind.

    High: 46 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 21. Calm wind.

    Low: 21 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 51. Calm wind.

    High: 51 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 21. Calm wind.

    Low: 21 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 53. Calm wind becoming southwest 5 to 9 mph in the morning. Winds could gust as high as 18 mph.

    High: 53 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 29. South wind 3 to 6 mph. Winds could gust as high as 18 mph.

    Low: 29 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 57. Light south wind increasing to 5 to 10 mph in the morning. Winds could gust as high as 22 mph.

    High: 57 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 34. South wind around 7 mph, with gusts as high as 23 mph.

    Low: 34 °F

    Partly Cloudy

Detailed Forecast

Tonight
Clear, with a low around 21. Calm wind.
Saturday
Sunny, with a high near 46. Calm wind.
Saturday Night
Mostly clear, with a low around 21. Calm wind.
Sunday
Sunny, with a high near 51. Calm wind.
Sunday Night
Clear, with a low around 21. Calm wind.
Monday
Sunny, with a high near 53. Calm wind becoming southwest 5 to 9 mph in the morning. Winds could gust as high as 18 mph.
Monday Night
Mostly clear, with a low around 29. South wind 3 to 6 mph. Winds could gust as high as 18 mph.
Tuesday
Sunny, with a high near 57. Light south wind increasing to 5 to 10 mph in the morning. Winds could gust as high as 22 mph.
Tuesday Night
Partly cloudy, with a low around 34. South wind around 7 mph, with gusts as high as 23 mph.
Wednesday
Mostly sunny, with a high near 58. South wind 6 to 13 mph, with gusts as high as 24 mph.
Wednesday Night
Mostly cloudy, with a low around 43. South wind 6 to 9 mph, with gusts as high as 24 mph.
Thursday
A 30 percent chance of rain. Partly sunny, with a high near 60. Southwest wind 6 to 11 mph, with gusts as high as 21 mph.
Thursday Night
A 20 percent chance of rain. Partly cloudy, with a low around 40. Light and variable wind.
Friday
A 30 percent chance of rain. Partly sunny, with a high near 60. Calm wind becoming south around 6 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Ontario WI
 43.73°N 90.58°W
Last Update:
11:06 pm CST Nov 13, 2026
Forecast Valid:
11pm CST Nov 13, 2026-6pm CST Nov 20, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation