Saint Charles Weather Forecast

    • 72
    • 98

    Slight Chance Thunderstorms

    • 71
    • 94

    Partly Sunny

    • 69
    • 94

    Partly Sunny

    • 69
    • 93

    Chance Rain Showers

    • 66
    • 88

    Chance Thunderstorms

    • 63
    • 87

    Chance Rain Showers

Today 14 Sep St. Charles

Mostly sunny. A slight chance of Showers and Thunderstorms in the afternoon. Hot with Highs in the upper 90s. Northwest Winds around 5 Mph. Chance of rain 20 percent.

Tonight 14 Sep St. Charles

Mostly cloudy with a slight chance of Showers and Thunderstorms in the Evening, then partly cloudy after midnight. Lows around 70. Northwest Winds around 5 Mph, becoming north around 5 Mph after midnight. Chance of rain 20 percent.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Saint Charles Temperature Statistics

September Temperature

St. Louis Lambert International Airport (6.2 miles)

  • Lowest 7 September, 2025

    52 °F

  • Average September

    69.4 °F

  • Highest 11 September, 2025

    89.1 °F

Climate (2020–Present)

St. Louis Lambert International Airport (6.2 miles)

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

  • Average Low 2020–2025

    50.3 °F

  • Average 2020–2025

    59.7 °F

  • Average High 2020–2025

    69.1 °F
Get WillyWeather+ to remove ads