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

Janesville-Rock County (KJVL)

Lat: 42.62°NLon: 89.04°WElev: 801ft.

Fog/Mist

41°F

5°C

Humidity 93%
Wind Speed Calm
Barometer 29.95 in
Dewpoint 39°F (4°C)
Visibility 4.00 mi
Last update 21 Mar 2:35 am CDT
Extended Forecast for

South Beloit IL

  • Overnight

    Overnight: Mostly cloudy, with a low around 40. Southeast wind around 5 mph.

    Low: 40 °F

    Mostly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 75. Southeast wind 5 to 10 mph becoming southwest 10 to 15 mph in the afternoon. Winds could gust as high as 30 mph.

    High: 75 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Increasing clouds, with a low around 46. West southwest wind 5 to 10 mph becoming northeast after midnight. Winds could gust as high as 20 mph.

    Low: 46 °F

    Increasing
    Clouds

  • Sunday

    Sunday: A 30 percent chance of rain, mainly before 1pm. Mostly cloudy, with a high near 47. North northeast wind around 15 mph, with gusts as high as 25 mph.

    High: 47 °F

    Chance Rain

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 26. North wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 26 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 46.

    High: 46 °F

    Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 31.

    Low: 31 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 56.

    High: 56 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 36.

    Low: 36 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Mostly cloudy, with a low around 40. Southeast wind around 5 mph.
Saturday
Mostly sunny, with a high near 75. Southeast wind 5 to 10 mph becoming southwest 10 to 15 mph in the afternoon. Winds could gust as high as 30 mph.
Saturday Night
Increasing clouds, with a low around 46. West southwest wind 5 to 10 mph becoming northeast after midnight. Winds could gust as high as 20 mph.
Sunday
A 30 percent chance of rain, mainly before 1pm. Mostly cloudy, with a high near 47. North northeast wind around 15 mph, with gusts as high as 25 mph.
Sunday Night
Partly cloudy, with a low around 26. North wind 5 to 15 mph, with gusts as high as 20 mph.
Monday
Sunny, with a high near 46.
Monday Night
Mostly cloudy, with a low around 31.
Tuesday
Mostly cloudy, with a high near 56.
Tuesday Night
Mostly cloudy, with a low around 36.
Wednesday
Mostly cloudy, with a high near 54.
Wednesday Night
Mostly cloudy, with a low around 43.
Thursday
A chance of showers. Partly sunny, with a high near 60.
Thursday Night
Partly cloudy, with a low around 28.
Friday
Mostly sunny, with a high near 44.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
South Beloit IL
 42.5°N 89.05°W
Last Update:
1:11 am CDT Mar 21, 2026
Forecast Valid:
2am CDT Mar 21, 2026-6pm CDT Mar 27, 2026
 
Forecast Discussion
 
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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