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.

Partly Cloudy

80°F

27°C

Humidity 67%
Wind Speed Calm
Barometer 30.20 in (1022.3 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index83°F (28°C)
Last update 5 Aug 11:53 am CDT
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny, with a high near 84. Calm wind becoming northeast around 5 mph.

    High: 84 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 8pm. Mostly clear, with a low around 67. Light east wind. Chance of precipitation is 20%.

    Low: 67 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 88. Light southeast wind.

    High: 88 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 69. Light southeast wind.

    Low: 69 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 90. Calm wind becoming southeast around 6 mph in the afternoon.

    High: 90 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 70.

    Low: 70 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 90.

    High: 90 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 72.

    Low: 72 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 91.

    High: 91 °F

    Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny, with a high near 84. Calm wind becoming northeast around 5 mph.
Tonight
A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 8pm. Mostly clear, with a low around 67. Light east wind. Chance of precipitation is 20%.
Wednesday
Mostly sunny, with a high near 88. Light southeast wind.
Wednesday Night
Mostly clear, with a low around 69. Light southeast wind.
Thursday
Sunny, with a high near 90. Calm wind becoming southeast around 6 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 70.
Friday
Sunny, with a high near 90.
Friday Night
Mostly clear, with a low around 72.
Saturday
Sunny, with a high near 91.
Saturday Night
Mostly clear, with a low around 73.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
Sunday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73.
Monday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
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 89.92°W (Elev. 551 ft)
Last Update:
11:51 am CDT Aug 5, 2025
Forecast Valid:
12pm CDT Aug 5, 2025-6pm CDT Aug 11, 2025
 
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