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

76°F

24°C

Humidity 72%
Wind Speed Calm
Barometer 30.22 in (1023.2 mb)
Dewpoint 67°F (19°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 12 Jul 8:55 am CDT
Extended Forecast for

Ontario WI

  • Today

    Today: Sunny, with a high near 90. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 90 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 67. Light southwest wind.

    Low: 67 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 94. Heat index values as high as 98. Calm wind becoming west around 6 mph in the morning.

    High: 94 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 68. Calm wind.

    Low: 68 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 95. Calm wind becoming west around 6 mph in the afternoon.

    High: 95 °F

    Hot

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 69. Light west wind.

    Low: 69 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 93. Light northwest wind.

    High: 93 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 67. Calm wind.

    Low: 67 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 91. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 91 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 90. Calm wind becoming southwest around 5 mph in the afternoon.
Tonight
Clear, with a low around 67. Light southwest wind.
Monday
Sunny, with a high near 94. Heat index values as high as 98. Calm wind becoming west around 6 mph in the morning.
Monday Night
Mostly clear, with a low around 68. Calm wind.
Tuesday
Sunny and hot, with a high near 95. Calm wind becoming west around 6 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 69. Light west wind.
Wednesday
Sunny, with a high near 93. Light northwest wind.
Wednesday Night
Mostly clear, with a low around 67. Calm wind.
Thursday
Mostly sunny, with a high near 91. Calm wind becoming southwest around 5 mph in the afternoon.
Thursday Night
A 20 percent chance of showers after 1am. Partly cloudy, with a low around 68. Light and variable wind.
Friday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91. Light southeast wind becoming south 5 to 9 mph in the morning. Winds could gust as high as 18 mph.
Friday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 68. South wind 3 to 7 mph.
Saturday
Mostly sunny, with a high near 90. South wind 5 to 10 mph becoming southwest in the afternoon. Winds could gust as high as 21 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:
7:56 am CDT Jul 12, 2026
Forecast Valid:
9am CDT Jul 12, 2026-6pm CDT Jul 18, 2026
 
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Additional Resources

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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