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

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Overcast

35°F

2°C

Humidity 85%
Wind Speed NE 3 mph
Barometer 30.12 in (1020.4 mb)
Dewpoint 31°F (-1°C)
Visibility 10.00 mi
Last update 3 Dec 4:53 pm CST
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: A 30 percent chance of snow. Cloudy, with a high near 35. South wind around 5 mph.

    High: 35 °F

    Chance Snow

  • Tonight

    Tonight: A chance of snow before 3am, then a chance of flurries between 3am and 4am. Cloudy, with a low around 14. Light and variable wind becoming north 8 to 13 mph in the evening. Winds could gust as high as 23 mph. Chance of precipitation is 50%.

    Low: 14 °F

    Chance Snow

  • Thursday

    Thursday: Cloudy through mid morning, then gradual clearing, with a high near 23. North wind 5 to 9 mph, with gusts as high as 20 mph.

    High: 23 °F

    Gradual
    Clearing

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 14. Calm wind becoming south around 5 mph after midnight.

    Low: 14 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 38. Calm wind becoming south around 6 mph in the morning.

    High: 38 °F

    Mostly Sunny

  • Friday Night

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

    Low: 25 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 39.

    High: 39 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: A slight chance of freezing rain after midnight. Mostly cloudy, with a low around 26. Chance of precipitation is 20%.

    Low: 26 °F

    Cloudy then
    Slight Chance
    Freezing Rain

  • Sunday

    Sunday: A 20 percent chance of snow before noon. Mostly cloudy, with a high near 34.

    High: 34 °F

    Slight Chance
    Snow then
    Mostly Cloudy

Detailed Forecast

This Afternoon
A 30 percent chance of snow. Cloudy, with a high near 35. South wind around 5 mph.
Tonight
A chance of snow before 3am, then a chance of flurries between 3am and 4am. Cloudy, with a low around 14. Light and variable wind becoming north 8 to 13 mph in the evening. Winds could gust as high as 23 mph. Chance of precipitation is 50%.
Thursday
Cloudy through mid morning, then gradual clearing, with a high near 23. North wind 5 to 9 mph, with gusts as high as 20 mph.
Thursday Night
Partly cloudy, with a low around 14. Calm wind becoming south around 5 mph after midnight.
Friday
Mostly sunny, with a high near 38. Calm wind becoming south around 6 mph in the morning.
Friday Night
Mostly cloudy, with a low around 25.
Saturday
Partly sunny, with a high near 39.
Saturday Night
A slight chance of freezing rain after midnight. Mostly cloudy, with a low around 26. Chance of precipitation is 20%.
Sunday
A 20 percent chance of snow before noon. Mostly cloudy, with a high near 34.
Sunday Night
Mostly cloudy, with a low around 16.
Monday
Mostly sunny, with a high near 32.
Monday Night
Partly cloudy, with a low around 23.
Tuesday
Mostly sunny, with a high near 44.
Tuesday Night
Mostly cloudy, with a low around 33.
Wednesday
A 20 percent chance of rain. Partly sunny, with a high near 50.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.92°W (Elev. 551 ft)
Last Update:
4:56 pm CST Dec 3, 2025
Forecast Valid:
5pm CST Dec 3, 2025-6pm CST Dec 10, 2025
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation