Janesville Weather Forecast

    • 15
    • 25

    Blustery

    • 24
    • 30

    Partly Sunny

    • 22
    • 36

    Mostly Cloudy

    • 18
    • 33

    Partly Sunny

    • 24
    • 36

    Mostly Cloudy

    • 19
    • 38

    Partly Sunny

Today 29 Dec Cumberland

Mostly sunny. Highs around 30. West Winds around 10 Mph.

Tonight 29 Dec Cumberland

Partly cloudy and not as cool. Near steady temperature in the upper 20s.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Janesville Temperature Statistics

December Temperature

Mattoon / Charleston, Coles County Memorial Airport (6.8 miles)

  • Lowest 14 December, 2025

    -7.1 °F

  • Average December

    30.7 °F

  • Highest 23 December, 2025

    61 °F

Climate (2020–Present)

Mattoon / Charleston, Coles County Memorial Airport (6.8 miles)

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  • Average Low 2020–2025

    45.8 °F

  • Average 2020–2025

    55.1 °F

  • Average High 2020–2025

    64.6 °F
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