O'Fallon Weather Forecast

    • 63
    • 83

    Chance Rain Showers

    • 65
    • 84

    Rain Showers

    • 59
    • 76

    Chance Rain Showers

    • 59
    • 79

    Slight Chance Thunderstorms

    • 63
    • 82

    Partly Sunny

    • 69
    • 86

    Slight Chance Thunderstorms

Today 12 Jun St. Charles

Sunny, cooler with Highs in the lower 80s. Northwest Winds around 5 Mph.

Tonight 12 Jun St. Charles

Mostly clear. Lows in the lower 60s. Northeast Winds around 5 Mph, becoming southeast after midnight.

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O'Fallon Temperature Statistics

June Temperature

St. Louis, Spirit Of St. Louis Airport (10.6 miles)

  • Lowest 3 June, 2026

    52.6 °F

  • Average June

    75.6 °F

  • Highest 9 June, 2026

    91.9 °F

Climate (2021–Present)

St. Louis, Spirit Of St. Louis Airport (10.6 miles)

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  • Average Low 2021–2026

    46.1 °F

  • Average 2021–2026

    57.4 °F

  • Average High 2021–2026

    68.9 °F
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