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.

Fair

45°F

7°C

Humidity 87%
Wind Speed Calm
Barometer 30.20 in
Dewpoint 41°F (5°C)
Visibility 10.00 mi
Last update 20 May 4:55 am CDT
Extended Forecast for

Janesville WI

  • Today

    Today: Mostly sunny, with a high near 63. North wind 5 to 10 mph.

    High: 63 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 42. East wind 5 to 10 mph.

    Low: 42 °F

    Partly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 62. East wind 10 to 15 mph.

    High: 62 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Increasing clouds, with a low around 46. East wind around 10 mph.

    Low: 46 °F

    Increasing
    Clouds

  • Friday

    Friday: A 40 percent chance of showers after 1pm. Mostly cloudy, with a high near 63. East wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 63 °F

    Mostly Cloudy
    then Chance
    Showers

  • Friday Night

    Friday Night: Showers likely before 10pm, then showers likely and possibly a thunderstorm between 10pm and 1am, then showers likely after 1am. Cloudy, with a low around 49. East wind 5 to 15 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 49 °F

    Showers
    Likely

  • Saturday

    Saturday: Mostly cloudy, with a high near 71. Northeast wind 5 to 10 mph becoming west in the afternoon.

    High: 71 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 52. North wind around 5 mph becoming calm in the evening.

    Low: 52 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Sunday

    Sunday: Partly sunny, with a high near 76.

    High: 76 °F

    Partly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 63. North wind 5 to 10 mph.
Tonight
Partly cloudy, with a low around 42. East wind 5 to 10 mph.
Thursday
Partly sunny, with a high near 62. East wind 10 to 15 mph.
Thursday Night
Increasing clouds, with a low around 46. East wind around 10 mph.
Friday
A 40 percent chance of showers after 1pm. Mostly cloudy, with a high near 63. East wind 10 to 15 mph, with gusts as high as 25 mph.
Friday Night
Showers likely before 10pm, then showers likely and possibly a thunderstorm between 10pm and 1am, then showers likely after 1am. Cloudy, with a low around 49. East wind 5 to 15 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Saturday
Mostly cloudy, with a high near 71. Northeast wind 5 to 10 mph becoming west in the afternoon.
Saturday Night
A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 52. North wind around 5 mph becoming calm in the evening.
Sunday
Partly sunny, with a high near 76.
Sunday Night
Partly cloudy, with a low around 53.
Memorial Day
Partly sunny, with a high near 82.
Monday Night
Partly cloudy, with a low around 56.
Tuesday
A 20 percent chance of showers. Mostly sunny, with a high near 84.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Janesville WI
 42.67°N 89.04°W (Elev. 774 ft)
Last Update:
2:36 am CDT May 20, 2026
Forecast Valid:
5am CDT May 20, 2026-6pm CDT May 26, 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