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

43°F

6°C

Humidity 96%
Wind Speed Calm
Barometer 30.08 in (1019.1 mb)
Dewpoint 42°F (6°C)
Visibility 10.00 mi
Last update 4 Oct 3:55 am CDT
Extended Forecast for

Ontario WI

  • Today

    Today: Sunny, with a high near 66. Northwest wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 66 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 40. Light north wind.

    Low: 40 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 66. Calm wind.

    High: 66 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 46. Calm wind becoming south around 5 mph after midnight.

    Low: 46 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 72. Breezy, with a south wind 8 to 16 mph, with gusts as high as 24 mph.

    High: 72 °F

    Sunny then
    Sunny and
    Breezy

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 50. Southwest wind around 6 mph becoming calm in the evening.

    Low: 50 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 71. Light west wind increasing to 6 to 11 mph in the afternoon. Winds could gust as high as 21 mph.

    High: 71 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 45. Light west wind.

    Low: 45 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 69. Calm wind becoming west 5 to 8 mph in the afternoon. Winds could gust as high as 18 mph.

    High: 69 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 66. Northwest wind 5 to 10 mph, with gusts as high as 20 mph.
Tonight
Clear, with a low around 40. Light north wind.
Monday
Sunny, with a high near 66. Calm wind.
Monday Night
Mostly clear, with a low around 46. Calm wind becoming south around 5 mph after midnight.
Tuesday
Sunny, with a high near 72. Breezy, with a south wind 8 to 16 mph, with gusts as high as 24 mph.
Tuesday Night
Mostly clear, with a low around 50. Southwest wind around 6 mph becoming calm in the evening.
Wednesday
Sunny, with a high near 71. Light west wind increasing to 6 to 11 mph in the afternoon. Winds could gust as high as 21 mph.
Wednesday Night
Partly cloudy, with a low around 45. Light west wind.
Thursday
Mostly sunny, with a high near 69. Calm wind becoming west 5 to 8 mph in the afternoon. Winds could gust as high as 18 mph.
Thursday Night
Partly cloudy, with a low around 46. Calm wind.
Friday
Mostly sunny, with a high near 68. Light west wind.
Friday Night
Partly cloudy, with a low around 48. Light southeast wind.
Saturday
Sunny, with a high near 73. Breezy, with a southeast wind 5 to 10 mph increasing to 11 to 16 mph in the afternoon. Winds could gust as high as 28 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:
2:16 am CDT Oct 4, 2026
Forecast Valid:
4am CDT Oct 4, 2026-6pm CDT Oct 10, 2026
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation