O'Fallon Weather Forecast

    • 12
    • 30

    Mostly Cloudy

    • 8
    • 23

    Chance Snow

    • 4
    • 19

    Mostly Cloudy

    • 3
    • 18

    Partly Sunny

    • 16
    • 29

    Mostly Cloudy

    • 21
    • 36

    Partly Sunny

    • 27
    • 38

    Chance Rain/Snow

Today 28 Jan St. Charles

Mostly sunny. Highs around 30. West Winds 5 to 10 Mph with Gusts up to 20 Mph.

Tonight 28 Jan St. Charles

Mostly cloudy. Not as cool with Lows around 12. West Winds around 5 Mph, becoming northeast after midnight.

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O'Fallon Temperature Statistics

January Temperature

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

  • Lowest 26 January, 2026

    -7.1 °F

  • Average January

    31.4 °F

  • Highest 6 January, 2026

    69.7 °F

Climate (2021–Present)

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

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  • Average Low 2021–2026

    45.9 °F

  • Average 2021–2026

    57.1 °F

  • Average High 2021–2026

    68.3 °F
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