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

Extreme Heat Lingers; Severe Thunderstorms for Portions of the Plains and Southeast; Heavy Rainfall Threats

Gusty winds and heavy rainfall may impact the Big Island of Hawaii as a nearby tropical system passes west of the islands. From the Southwest U.S., Rockies and across the Gulf Coast, heavy rainfall could lead to isolated flash flooding. Severe thunderstorms are expected for areas of the Plains, Gulf Coast and Southeast through Tuesday. Extreme heat lingers for the southern Plains and Southwest. Read More >

Current conditions at

St. Louis Lambert International Airport (KSTL)

Lat: 38.75°NLon: 90.37°WElev: 604ft.

Mostly Cloudy

80°F

27°C

Humidity 49%
Wind Speed Calm
Barometer 30.09 in (1017.9 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Heat Index81°F (27°C)
Last update 24 Aug 12:51 pm CDT
Extended Forecast for

Saint Charles MO

  • This Afternoon

    This Afternoon: Partly sunny, with a high near 82. Light and variable wind.

    High: 82 °F

    Partly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 67. East wind 3 to 5 mph.

    Low: 67 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly cloudy, then gradually becoming sunny, with a high near 86. Southeast wind 3 to 6 mph.

    High: 86 °F

    Decreasing
    Clouds

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 70. East wind around 5 mph becoming calm in the evening.

    Low: 70 °F

    Partly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. Calm wind becoming west around 6 mph in the afternoon.

    High: 89 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 68.

    Low: 68 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: Sunny, with a high near 86.

    High: 86 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 66.

    Low: 66 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 86.

    High: 86 °F

    Sunny

Detailed Forecast

This Afternoon
Partly sunny, with a high near 82. Light and variable wind.
Tonight
Partly cloudy, with a low around 67. East wind 3 to 5 mph.
Tuesday
Mostly cloudy, then gradually becoming sunny, with a high near 86. Southeast wind 3 to 6 mph.
Tuesday Night
Partly cloudy, with a low around 70. East wind around 5 mph becoming calm in the evening.
Wednesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. Calm wind becoming west around 6 mph in the afternoon.
Wednesday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 68.
Thursday
Sunny, with a high near 86.
Thursday Night
Mostly clear, with a low around 66.
Friday
Sunny, with a high near 86.
Friday Night
Mostly clear, with a low around 68.
Saturday
Mostly sunny, with a high near 89.
Saturday Night
Partly cloudy, with a low around 72.
Sunday
Sunny, with a high near 93.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Charles MO
 38.78°N 90.51°W (Elev. 597 ft)
Last Update:
1:16 pm CDT Aug 24, 2026
Forecast Valid:
1pm CDT Aug 24, 2026-6pm CDT Aug 30, 2026
 
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