O'Fallon Weather Forecast

    • 66
    • 81

    Rain Showers

    • 72
    • 85

    Chance Thunderstorms

    • 75
    • 94

    Mostly Sunny

    • 76
    • 96

    Mostly Sunny

    • 76
    • 98

    Hot

    • 76
    • 97

    Hot

Today 26 Jun St. Charles

Showers with a chance of Thunderstorms in the Morning, then Showers and Thunderstorms likely in the afternoon. Some Thunderstorms may produce heavy rainfall in the morning. Some Thunderstorms may produce heavy rainfall in the afternoon. Highs around 80. Southeast Winds 5 to 10 Mph, becoming southwest in the afternoon. Chance of rain near 100 percent.

Tonight 26 Jun St. Charles

Showers with a chance of Thunderstorms. Some Thunderstorms may produce heavy rainfall. Near steady temperature around 70. Southeast Winds around 5 Mph. Chance of rain near 100 percent.

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  • Temperature Real-Time

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

    74 °F

  • Highest 9 June, 2026

    93.7 °F

Climate (2021–2026)

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

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  • Average Low 2021–2026

    46 °F

  • Average 2021–2026

    57.4 °F

  • Average High 2021–2026

    68.8 °F
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