Janesville Weather Forecast

    • 65
    • 68

    Rain Showers

    • 55
    • 72

    Rain Showers Likely

    • 59
    • 70

    Rain Showers

    • 60
    • 74

    Rain Showers Likely

    • 62
    • 75

    Rain Showers

    • 57
    • 74

    Chance Rain Showers

Today 14 Sep Bremer

Showers likely with a slight chance of Thunderstorms. Some Thunderstorms may produce heavy rainfall. Breezy with Highs in the upper 60s. Southeast Winds 20 to 25 Mph with Gusts up to 35 Mph. Chance of rain 70 percent.

Tonight 14 Sep Bremer

A chance of Thunderstorms. Showers. Some Thunderstorms may produce heavy rainfall. Locally heavy rainfall possible in the evening. Breezy and not as cool. Near steady temperature in the mid 60s. Southeast Winds 20 to 25 Mph, becoming southwest 15 to 20 Mph after midnight. Chance of rain 90 percent.

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Janesville Temperature Statistics

September Temperature

Waterloo, Waterloo Municipal Airport (6.8 miles)

  • Lowest 10 September, 2026

    54.6 °F

  • Average September

    74.9 °F

  • Highest 1 September, 2026

    92.6 °F

Climate (2021–2026)

Waterloo, Waterloo Municipal Airport (6.8 miles)

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  • Average Low 2021–2026

    40.2 °F

  • Average 2021–2026

    51.1 °F

  • Average High 2021–2026

    61.9 °F
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