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.

Overcast

56°F

13°C

Humidity 84%
Wind Speed Calm
Barometer 30.17 in (1022.2 mb)
Dewpoint 51°F (11°C)
Visibility 10.00 mi
Last update 14 Oct 7:55 pm CDT
Extended Forecast for

Ontario WI

  • Tonight

    Tonight: Mostly cloudy, with a low around 43. East wind 3 to 6 mph.

    Low: 43 °F

    Mostly Cloudy

  • Thursday

    Thursday: Showers, mainly after 9am. High near 59. East wind around 6 mph becoming light and variable in the afternoon. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.

    High: 59 °F

    Showers
    Likely then
    Showers

  • Thursday Night

    Thursday Night: Showers, mainly before midnight. Low around 39. Northwest wind 7 to 13 mph, with gusts as high as 29 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 39 °F

    Showers then
    Chance
    Showers

  • Friday

    Friday: A 50 percent chance of showers before 1pm. Mostly cloudy, with a high near 54. Breezy, with a northwest wind 16 to 21 mph, with gusts as high as 31 mph. New precipitation amounts of less than a tenth of an inch possible.

    High: 54 °F

    Chance
    Showers and
    Breezy

  • Friday Night

    Friday Night: Widespread frost, mainly after 2am. Otherwise, mostly clear, with a low around 28. North wind 5 to 8 mph becoming calm in the evening. Winds could gust as high as 21 mph.

    Low: 28 °F

    Mostly Clear
    then Frost

  • Saturday

    Saturday: Widespread frost, mainly before 8am. Otherwise, sunny, with a high near 59. Light south wind becoming southwest 6 to 11 mph in the afternoon. Winds could gust as high as 23 mph.

    High: 59 °F

    Frost then
    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 36. Southwest wind around 8 mph, with gusts as high as 23 mph.

    Low: 36 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 65. Breezy, with a southwest wind 10 to 17 mph, with gusts as high as 26 mph.

    High: 65 °F

    Sunny and
    Breezy

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 41. South wind 5 to 9 mph becoming calm after midnight. Winds could gust as high as 24 mph.

    Low: 41 °F

    Partly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 43. East wind 3 to 6 mph.
Thursday
Showers, mainly after 9am. High near 59. East wind around 6 mph becoming light and variable in the afternoon. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.
Thursday Night
Showers, mainly before midnight. Low around 39. Northwest wind 7 to 13 mph, with gusts as high as 29 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.
Friday
A 50 percent chance of showers before 1pm. Mostly cloudy, with a high near 54. Breezy, with a northwest wind 16 to 21 mph, with gusts as high as 31 mph. New precipitation amounts of less than a tenth of an inch possible.
Friday Night
Widespread frost, mainly after 2am. Otherwise, mostly clear, with a low around 28. North wind 5 to 8 mph becoming calm in the evening. Winds could gust as high as 21 mph.
Saturday
Widespread frost, mainly before 8am. Otherwise, sunny, with a high near 59. Light south wind becoming southwest 6 to 11 mph in the afternoon. Winds could gust as high as 23 mph.
Saturday Night
Clear, with a low around 36. Southwest wind around 8 mph, with gusts as high as 23 mph.
Sunday
Sunny, with a high near 65. Breezy, with a southwest wind 10 to 17 mph, with gusts as high as 26 mph.
Sunday Night
Partly cloudy, with a low around 41. South wind 5 to 9 mph becoming calm after midnight. Winds could gust as high as 24 mph.
Monday
Mostly sunny, with a high near 68. Calm wind becoming southwest around 5 mph in the afternoon.
Monday Night
Mostly clear, with a low around 40. Calm wind.
Tuesday
Sunny, with a high near 70. Calm wind becoming south 5 to 7 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 46. Light south wind.
Wednesday
A 20 percent chance of showers. Mostly sunny, with a high near 72. Light south wind increasing to 5 to 10 mph in the morning. Winds could gust as high as 20 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:
6:46 pm CDT Oct 14, 2026
Forecast Valid:
8pm CDT Oct 14, 2026-6pm CDT Oct 21, 2026
 
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Additional Resources

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High Temperature

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Chance of Precipitation