Janesville Weather Forecast

    • 32
    • 44

    Increasing Clouds

    • 36
    • 53

    Mostly Cloudy

    • 16
    • 40

    Chance Rain/Snow

    • 22
    • 29

    Mostly Cloudy

    • 21
    • 37

    Mostly Cloudy

    • 11
    • 28

    Mostly Cloudy

Today 12 Jan Cumberland

Sunny. Not as cool with Highs in the mid 40s. Southwest Winds 10 to 15 Mph with Gusts up to 25 Mph.

Tonight 12 Jan Cumberland

Mostly clear in the Evening, then becoming partly cloudy. Lows in the lower 30s. Southwest Winds 5 to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Janesville Temperature Statistics

January Temperature

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

  • Lowest 4 January, 2026

    21.9 °F

  • Average January

    38.5 °F

  • Highest 8 January, 2026

    64 °F

Climate (2021–Present)

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

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  • Average Low 2021–2026

    45.8 °F

  • Average 2021–2026

    55.2 °F

  • Average High 2021–2026

    64.6 °F
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