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.

Fair

96°F

36°C

Humidity 34%
Wind Speed N 3 mph
Barometer 29.93 in (1012.9 mb)
Dewpoint 63°F (17°C)
Visibility 10.00 mi
Heat Index98°F (37°C)
Last update 14 Sep 4:53 pm CDT
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: A 20 percent chance of showers and thunderstorms. Mostly sunny and hot, with a high near 98. North wind around 5 mph.

    High: 98 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 9pm. Partly cloudy, with a low around 69. Northeast wind 3 to 5 mph.

    Low: 69 °F

    Slight Chance
    T-storms then
    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 93. East wind 3 to 7 mph.

    High: 93 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 64. East wind 3 to 6 mph.

    Low: 64 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 93. East wind 3 to 6 mph.

    High: 93 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 65.

    Low: 65 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 93.

    High: 93 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 65.

    Low: 65 °F

    Partly Cloudy

  • Thursday

    Thursday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 92.

    High: 92 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

Detailed Forecast

This Afternoon
A 20 percent chance of showers and thunderstorms. Mostly sunny and hot, with a high near 98. North wind around 5 mph.
Tonight
A 20 percent chance of showers and thunderstorms before 9pm. Partly cloudy, with a low around 69. Northeast wind 3 to 5 mph.
Monday
Sunny, with a high near 93. East wind 3 to 7 mph.
Monday Night
Mostly clear, with a low around 64. East wind 3 to 6 mph.
Tuesday
Sunny, with a high near 93. East wind 3 to 6 mph.
Tuesday Night
Mostly clear, with a low around 65.
Wednesday
Sunny, with a high near 93.
Wednesday Night
Partly cloudy, with a low around 65.
Thursday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 92.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 65.
Friday
A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 86.
Friday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 64.
Saturday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 83.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 61.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 83.
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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:
5:01 pm CDT Sep 14, 2025
Forecast Valid:
5pm CDT Sep 14, 2025-6pm CDT Sep 21, 2025
 
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