Saint Charles Weather Forecast

    • 63
    • 81

    Slight Chance Rain Showers

    • 63
    • 83

    Chance Thunderstorms

    • 64
    • 85

    Mostly Cloudy

    • 62
    • 82

    Mostly Cloudy

    • 61
    • 82

    Partly Sunny

    • 60
    • 81

    Partly Sunny

Today 26 May St. Charles

Mostly cloudy. A slight chance of Showers and Thunderstorms. Near steady temperature in the upper 70s. East Winds 5 to 10 Mph. Chance of rain 20 percent.

Tonight 26 May St. Charles

Mostly cloudy with a slight chance of Thunderstorms. A slight chance of Showers in the Evening, then a chance of Showers after midnight. Lows in the lower 60s. East Winds around 5 Mph, becoming north after midnight. Chance of rain 50 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Saint Charles Temperature Statistics

May Temperature

St. Louis Lambert International Airport (6.2 miles)

  • Lowest 7 May, 2026

    42.7 °F

  • Average May

    64.9 °F

  • Highest 17 May, 2026

    87.7 °F

Climate (2021–Present)

St. Louis Lambert International Airport (6.2 miles)

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  • Average Low 2021–2026

    50.6 °F

  • Average 2021–2026

    60.1 °F

  • Average High 2021–2026

    69.7 °F
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