O'Fallon Weather Forecast

    • 64
    • 82

    Increasing Clouds

    • 60
    • 84

    Rain Likely

    • 64
    • 75

    Rain

    • 60
    • 79

    Rain

    • 59
    • 80

    Rain Likely

    • 41
    • 70

    Rain Likely

    • 38
    • 59

    Partly Sunny

Today 30 Mar St. Clair

Sunny and not as cool. Near steady temperature in the lower 80s. Southwest Winds 15 to 20 Mph with Gusts up to 30 Mph.

Tonight 30 Mar St. Clair

Partly cloudy. Lows in the mid 60s. South Winds 15 to 20 Mph.

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O'Fallon Temperature Statistics

March Temperature

Belleville, Scott AFB/MidAmerica Airport (4.3 miles)

  • Lowest 16 March, 2026

    23.9 °F

  • Average March

    54 °F

  • Highest 22 March, 2026

    91.8 °F

Climate (2021–Present)

Belleville, Scott AFB/MidAmerica Airport (4.3 miles)

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  • Average Low 2021–2026

    47.6 °F

  • Average 2021–2026

    57.6 °F

  • Average High 2021–2026

    67.9 °F
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