National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Overcast

35°F

2°C

Humidity 61%
Wind Speed S 12 mph
Barometer 29.96 in (1015.0 mb)
Dewpoint 23°F (-5°C)
Visibility 10.00 mi
Wind Chill27°F (-3°C)
Last update 5 Feb 1:53 pm CST
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: Partly sunny, with a high near 38. South wind 7 to 10 mph.

    High: 38 °F

    Partly Sunny

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming mostly clear, with a low around 29. South wind 5 to 8 mph becoming west after midnight.

    Low: 29 °F

    Decreasing
    Clouds

  • Friday

    Friday: Sunny through mid morning, then becoming mostly cloudy, with a high near 46. Breezy, with a west wind 11 to 20 mph becoming northwest in the afternoon. Winds could gust as high as 34 mph.

    High: 46 °F

    Mostly Cloudy
    and Breezy

  • Friday Night

    Friday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 23. Northwest wind 6 to 16 mph, with gusts as high as 28 mph.

    Low: 23 °F

    Decreasing
    Clouds

  • Saturday

    Saturday: Sunny, with a high near 35. North wind around 6 mph becoming southeast in the afternoon.

    High: 35 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 25.

    Low: 25 °F

    Mostly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 51.

    High: 51 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 29.

    Low: 29 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 56.

    High: 56 °F

    Sunny

Detailed Forecast

This Afternoon
Partly sunny, with a high near 38. South wind 7 to 10 mph.
Tonight
Mostly cloudy, then gradually becoming mostly clear, with a low around 29. South wind 5 to 8 mph becoming west after midnight.
Friday
Sunny through mid morning, then becoming mostly cloudy, with a high near 46. Breezy, with a west wind 11 to 20 mph becoming northwest in the afternoon. Winds could gust as high as 34 mph.
Friday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 23. Northwest wind 6 to 16 mph, with gusts as high as 28 mph.
Saturday
Sunny, with a high near 35. North wind around 6 mph becoming southeast in the afternoon.
Saturday Night
Mostly cloudy, with a low around 25.
Sunday
Mostly sunny, with a high near 51.
Sunday Night
Mostly clear, with a low around 29.
Monday
Sunny, with a high near 56.
Monday Night
Mostly clear, with a low around 40.
Tuesday
A 20 percent chance of rain. Partly sunny, with a high near 63.
Tuesday Night
A 40 percent chance of rain. Cloudy, with a low around 43.
Wednesday
A 30 percent chance of rain. Mostly cloudy, with a high near 55.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.92°W (Elev. 551 ft)
Last Update:
12:26 pm CST Feb 5, 2026
Forecast Valid:
2pm CST Feb 5, 2026-6pm CST Feb 11, 2026
 
Forecast Discussion
 
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Additional Resources

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High Temperature

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Chance of Precipitation