St. Charles Airport Weather Forecast

    • 64
    • 94

    Mostly Sunny

    • 65
    • 93

    Mostly Sunny

    • 64
    • 93

    Mostly Sunny

    • 67
    • 94

    Chance Thunderstorms

    • 64
    • 85

    Chance Thunderstorms

    • 64
    • 85

    Chance Rain Showers

    • 64
    • 82

    Slight Chance Thunderstorms

Today 15 Sep St. Charles

Sunny. Near steady temperature in the lower 90s. East Winds 5 to 10 Mph.

Tonight 15 Sep St. Charles

Mostly clear. Lows in the mid 60s. East Winds around 5 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

St. Charles Airport Temperature Statistics

September Temperature

St. Charles, St. Charles County Smartt Airport (6.2 miles)

  • Lowest 7 September, 2025

    48 °F

  • Average September

    68.7 °F

  • Highest 13 September, 2025

    95 °F

Climate (2020–Present)

St. Charles, St. Charles County Smartt Airport (6.2 miles)

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

  • Average Low 2020–2025

    47.3 °F

  • Average 2020–2025

    57.6 °F

  • Average High 2020–2025

    68.4 °F
Get WillyWeather+ to remove ads