Janesville Weather Forecast

    • 59
    • 83

    Mostly Sunny

    • 58
    • 83

    Mostly Sunny

    • 58
    • 83

    Partly Sunny

    • 59
    • 83

    Chance Rain Showers

    • 57
    • 74

    Chance Thunderstorms

    • 54
    • 72

    Chance Rain Showers

Today 15 Sep Rock

Sunny. Patchy fog in the morning. Highs in the lower 80s. Southeast Winds 5 to 10 Mph.

Tonight 15 Sep Rock

Clear. Lows in the upper 50s. East Winds up to 10 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Janesville Temperature Statistics

September Temperature

Janesville-Rock County (4.3 miles)

  • Lowest 7 September, 2025

    39.2 °F

  • Average September

    56.8 °F

  • Highest 12 September, 2025

    82.4 °F

Climate (2020–Present)

Janesville-Rock County (4.3 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    40.4 °F

  • Average 2020–2025

    48.7 °F

  • Average High 2020–2025

    60.2 °F
Get WillyWeather+ to remove ads