Glenn Weather Forecast

    • 27
    • 56

    Rain Showers

    • 32
    • 42

    Mostly Sunny

    • 28
    • 54

    Partly Sunny

    • 27
    • 45

    Partly Sunny

    • 41
    • 47

    Mostly Cloudy

    • 52
    • 62

    Mostly Cloudy

    • 56
    • 66

    Mostly Cloudy

Today 18 Dec Jackson

Showers. Highs in the mid 50s. Temperature falling into the upper 40s late. Southwest Winds 5 to 10 Mph with Gusts up to 35 Mph. Chance of rain near 100 percent.

Tonight 18 Dec Jackson

Mostly cloudy this Evening, then becoming partly cloudy. Much cooler with Lows in the upper 20s. West Winds 15 to 20 Mph with Gusts up to 35 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Glenn Temperature Statistics

December Temperature

Southern Illinois Airport (18 miles)

  • Lowest 14 December, 2025

    8.1 °F

  • Average December

    31 °F

  • Highest 6 December, 2025

    48.9 °F

Climate (2020–Present)

Southern Illinois Airport (18 miles)

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  • Average Low 2020–2025

    47.9 °F

  • Average 2020–2025

    58.2 °F

  • Average High 2020–2025

    68.7 °F
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