Johnstown Weather Forecast

    • 29
    • 38

    Chance Rain

    • 15
    • 37

    Slight Chance Rain

    • 18
    • 28

    Partly Sunny

    • 37
    • 43

    Slight Chance Rain

    • 22
    • 43

    Chance Snow

    • 16
    • 33

    Slight Chance Rain/Snow

    • 3
    • 23

    Mostly Cloudy

Today 6 Dec Cumberland

Partly sunny. Highs in the upper 30s. South Winds around 5 Mph.

Tonight 6 Dec Cumberland

Cloudy. A slight chance of Rain, freezing rain and freezing drizzle after midnight. Patchy fog after midnight. Near steady temperature in the lower 30s. Southeast Winds around 5 Mph. Chance of precipitation 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Johnstown Temperature Statistics

December Temperature

Mattoon / Charleston, Coles County Memorial Airport (7.5 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 (7.5 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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