O'Fallon Weather Forecast

    • 56
    • 79

    Slight Chance Thunderstorms

    • 56
    • 79

    Thunderstorms

    • 38
    • 68

    Slight Chance Rain Showers

    • 34
    • 51

    Mostly Sunny

    • 52
    • 69

    Mostly Sunny

    • 56
    • 74

    Mostly Cloudy

Today 13 Mar St. Clair

Sunny with isolated Showers and Thunderstorms. Near steady temperature in the upper 70s. Southeast Winds 5 to 10 Mph. Chance of rain 20 percent.

Tonight 13 Mar St. Clair

Mostly clear in the Evening, then becoming partly cloudy. Lows in the upper 50s. Southeast Winds 5 to 10 Mph.

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  • Temperature Real-Time

O'Fallon Temperature Statistics

March Temperature

Belleville, Scott AFB/MidAmerica Airport (4.3 miles)

  • Lowest 2 March, 2025

    22.5 °F

  • Average March

    46.1 °F

  • Highest 11 March, 2025

    79.2 °F

Climate (2020–Present)

Belleville, Scott AFB/MidAmerica Airport (4.3 miles)

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  • Average Low 2020–2025

    47.1 °F

  • Average 2020–2025

    56.9 °F

  • Average High 2020–2025

    67.1 °F
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