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

73°F

23°C

Humidity 94%
Wind Speed N 3 mph
Barometer 30.05 in (1017.1 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Last update 14 Oct 11:53 am CDT
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: A chance of showers and thunderstorms between 1pm and 4pm, then a slight chance of showers. Cloudy, with a high near 76. Northwest wind around 5 mph. Chance of precipitation is 30%.

    High: 76 °F

    Chance
    Showers

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly after 4am. Cloudy, with a low around 67. Light and variable wind.

    Low: 67 °F

    Cloudy then
    Chance
    Showers

  • Thursday

    Thursday: Showers and thunderstorms, mainly before 1pm. High near 84. East wind 5 to 11 mph becoming southwest in the afternoon. Chance of precipitation is 80%.

    High: 84 °F

    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 51. West wind 8 to 18 mph, with gusts as high as 26 mph. Chance of precipitation is 50%.

    Low: 51 °F

    Chance
    Showers

  • Friday

    Friday: Mostly cloudy, with a high near 57. Breezy, with a northwest wind 20 to 22 mph, with gusts as high as 30 mph.

    High: 57 °F

    Mostly Cloudy
    and Breezy

  • Friday Night

    Friday Night: Partly cloudy, with a low around 40.

    Low: 40 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 61.

    High: 61 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 38.

    Low: 38 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 69.

    High: 69 °F

    Sunny

Detailed Forecast

This Afternoon
A chance of showers and thunderstorms between 1pm and 4pm, then a slight chance of showers. Cloudy, with a high near 76. Northwest wind around 5 mph. Chance of precipitation is 30%.
Tonight
A 30 percent chance of showers and thunderstorms, mainly after 4am. Cloudy, with a low around 67. Light and variable wind.
Thursday
Showers and thunderstorms, mainly before 1pm. High near 84. East wind 5 to 11 mph becoming southwest in the afternoon. Chance of precipitation is 80%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 51. West wind 8 to 18 mph, with gusts as high as 26 mph. Chance of precipitation is 50%.
Friday
Mostly cloudy, with a high near 57. Breezy, with a northwest wind 20 to 22 mph, with gusts as high as 30 mph.
Friday Night
Partly cloudy, with a low around 40.
Saturday
Sunny, with a high near 61.
Saturday Night
Clear, with a low around 38.
Sunday
Sunny, with a high near 69.
Sunday Night
Partly cloudy, with a low around 45.
Monday
Mostly sunny, with a high near 73.
Monday Night
Partly cloudy, with a low around 49.
Tuesday
Mostly sunny, with a high near 78.
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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:
11:31 am CDT Oct 14, 2026
Forecast Valid:
12pm CDT Oct 14, 2026-6pm CDT Oct 20, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation