Severe Weather and Heavy Rain from the Great Lakes to the Mid-Atlantic; Heat Persists in the East

Widespread strong thunderstorms with damaging winds and locally heavy rain are expected from the Upper Ohio Valley into the southern Mid-Atlantic today and portions of the central Appalachians and Carolinas on Saturday. Monsoonal moisture will bring a flash flooding threat to the Desert Southwest. Sweltering heat persists from the Plains to the southern Mid-Atlantic through tonight. Read More >

Current conditions at

St. Louis Lambert International Airport (KSTL)

Lat: 38.75°NLon: 90.37°WElev: 604ft.

A Few Clouds

92°F

33°C

Humidity 52%
Wind Speed W 10 mph
Barometer 30.01 in (1014.6 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index100°F (38°C)
Last update 4 Sep 10:51 am CDT
Extended Forecast for

Saint Charles MO

Extreme Heat Warning September 4, 11:05am until September 5, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning September 4, 11:05am until September 5, 08:00pm

    NOW until 8:00pm Sat

    Extreme Heat Warning

  • Today

    High: 99 °F

    Hot

  • Tonight

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

    Low: 76 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny and hot, with a high near 99. Heat index values as high as 107. Calm wind becoming northwest around 5 mph in the afternoon.

    High: 99 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 74. Light and variable wind.

    Low: 74 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 93. Northeast wind 3 to 7 mph.

    High: 93 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 70.

    Low: 70 °F

    Partly Cloudy

  • Labor Day

    Labor Day: Sunny, with a high near 92.

    High: 92 °F

    Sunny

  • Monday Night

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

    Low: 70 °F

    Mostly Clear

Detailed Forecast

Today
Mostly sunny and hot, with a high near 99. Heat index values as high as 105. Southwest wind around 6 mph.
Tonight
Mostly clear, with a low around 76. Calm wind.
Saturday
Mostly sunny and hot, with a high near 99. Heat index values as high as 107. Calm wind becoming northwest around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 74. Light and variable wind.
Sunday
Sunny, with a high near 93. Northeast wind 3 to 7 mph.
Sunday Night
Partly cloudy, with a low around 70.
Labor Day
Sunny, with a high near 92.
Monday Night
Mostly clear, with a low around 70.
Tuesday
Sunny and hot, with a high near 97.
Tuesday Night
Mostly clear, with a low around 77.
Wednesday
Sunny and hot, with a high near 99.
Wednesday Night
A 20 percent chance of showers. Mostly clear, with a low around 77.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 94.
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ABOUT THIS FORECAST

 
Point Forecast:
Saint Charles MO
 38.78°N 90.54°W (Elev. 515 ft)
9:26 am CDT Sep 4, 2026
11am CDT Sep 4, 2026-6pm CDT Sep 10, 2026
 
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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