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

Hazardous Weather Conditions

Current conditions at

St. Louis, Spirit Of St. Louis Airport (KSUS)

Lat: 38.66°NLon: 90.66°WElev: 463ft.

Fair

90°F

32°C

Humidity 58%
Wind Speed S 8 mph
Barometer 30.07 in (1017.1 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index99°F (37°C)
Last update 15 Aug 10:54 am CDT
Extended Forecast for

O'Fallon MO

Heat Advisory August 15, 12:00pm until August 18, 08:00pm
Click here for hazard details and duration
Heat Advisory

  • Today

    Today: Sunny, with a high near 95. Heat index values as high as 103. South wind 3 to 5 mph.

    High: 95 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 76. Southeast wind around 5 mph.

    Low: 76 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 98. Heat index values as high as 107. South wind 3 to 6 mph.

    High: 98 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 76. Calm wind.

    Low: 76 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny and hot, with a high near 97. Light south wind.

    High: 97 °F

    Hot

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 76.

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 98.

    High: 98 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 77.

    Low: 77 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 97.

    High: 97 °F

    Sunny then
    Slight Chance
    T-storms

Detailed Forecast

Today
Sunny, with a high near 95. Heat index values as high as 103. South wind 3 to 5 mph.
Tonight
Mostly clear, with a low around 76. Southeast wind around 5 mph.
Saturday
Sunny and hot, with a high near 98. Heat index values as high as 107. South wind 3 to 6 mph.
Saturday Night
Mostly clear, with a low around 76. Calm wind.
Sunday
Sunny and hot, with a high near 97. Light south wind.
Sunday Night
Mostly clear, with a low around 76.
Monday
Sunny and hot, with a high near 98.
Monday Night
Mostly clear, with a low around 77.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 97.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 74.
Wednesday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88.
Wednesday Night
Partly cloudy, with a low around 69.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 86.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon MO
 38.81°N 90.71°W (Elev. 502 ft)
Last Update:
10:26 am CDT Aug 15, 2025
Forecast Valid:
11am CDT Aug 15, 2025-6pm CDT Aug 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