Glenn Weather Forecast

    • 71
    • 94

    Becoming Sunny

    • 70
    • 97

    Hot

    • 65
    • 84

    Rain Showers

    • 66
    • 87

    Chance Rain Showers

    • 66
    • 90

    Slight Chance Thunderstorms

    • 66
    • 90

    Mostly Sunny

Today 8 Sep Jackson

Sunny, hot with Highs in the mid 90s. South Winds around 5 Mph.

Tonight 8 Sep Jackson

Partly cloudy in the Evening, then becoming mostly clear. Lows in the lower 70s. South Winds 5 to 10 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Glenn Temperature Statistics

September Temperature

Southern Illinois Airport (18 miles)

  • Lowest 1 September, 2026

    70.6 °F

  • Average September

    89.2 °F

  • Highest 5 September, 2026

    100.4 °F

Climate (2021–2026)

Southern Illinois Airport (18 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    48.2 °F

  • Average 2021–2026

    58.8 °F

  • Average High 2021–2026

    69.4 °F
Get WillyWeather+ to remove ads