Janesville Weather Forecast

    • 15
    • 35

    Decreasing Clouds

    • 17
    • 27

    Partly Sunny

    • 37
    • 43

    Mostly Cloudy

    • 22
    • 42

    Chance Snow

    • 16
    • 32

    Slight Chance Rain/Snow

    • 3
    • 23

    Mostly Cloudy

Today 7 Dec Cumberland

Cloudy. A slight chance of rain in the morning. Patchy fog. Highs in the mid 30s. Temperature falling into the lower 30s in the afternoon. Southwest Winds 5 to 10 Mph, becoming north 10 to 15 Mph in the afternoon. Chance of rain 20 percent.

Tonight 7 Dec Cumberland

Mostly cloudy. Much cooler with Lows around 16. North Winds 5 to 10 Mph.

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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 4 December, 2025

    8.1 °F

  • Average December

    21.2 °F

  • Highest 3 December, 2025

    30.9 °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

    55.2 °F

  • Average High 2020–2025

    64.6 °F
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