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.

Fair

48°F

9°C

Humidity 100%
Wind Speed Calm
Barometer 30.00 in (1015.8 mb)
Dewpoint 48°F (9°C)
Visibility 9.00 mi
Last update 11 Oct 5:53 am CDT
Extended Forecast for

O'Fallon IL

  • Today

    Today: Sunny, with a high near 88. Light and variable wind.

    High: 88 °F

    Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 65. Light and variable wind becoming south around 5 mph in the evening.

    Low: 65 °F

    Increasing
    Clouds

  • Columbus Day

    Columbus Day: Sunny, with a high near 94. Southwest wind 6 to 13 mph.

    High: 94 °F

    Sunny

  • Monday Night

    Monday Night: Clear, with a low around 69. Southwest wind 8 to 10 mph.

    Low: 69 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 94. West wind 7 to 10 mph.

    High: 94 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70.

    Low: 70 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 84. Chance of precipitation is 70%.

    High: 84 °F

    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 64.

    Low: 64 °F

    Chance
    Showers

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%.

    High: 79 °F

    Showers
    Likely

Detailed Forecast

Today
Sunny, with a high near 88. Light and variable wind.
Tonight
Increasing clouds, with a low around 65. Light and variable wind becoming south around 5 mph in the evening.
Columbus Day
Sunny, with a high near 94. Southwest wind 6 to 13 mph.
Monday Night
Clear, with a low around 69. Southwest wind 8 to 10 mph.
Tuesday
Sunny, with a high near 94. West wind 7 to 10 mph.
Tuesday Night
A 40 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70.
Wednesday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 84. Chance of precipitation is 70%.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 64.
Thursday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 56.
Friday
A 20 percent chance of showers. Partly sunny, with a high near 68. Breezy.
Friday Night
Partly cloudy, with a low around 43.
Saturday
Sunny, with a high near 61.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.89°W (Elev. 541 ft)
Last Update:
5:26 am CDT Oct 11, 2026
Forecast Valid:
6am CDT Oct 11, 2026-6pm CDT Oct 17, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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