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

Hazardous Weather Conditions

Current conditions at

St. Charles, St. Charles County Smartt Airport (KSET)

Lat: 38.93°NLon: 90.43°WElev: 436ft.

Fair

96°F

36°C

Humidity 41%
Wind Speed Calm
Barometer 29.98 in (1014.5 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index101°F (38°C)
Last update 18 Aug 2:54 pm CDT
Extended Forecast for

3 Miles SSW Dow IL

Heat Advisory August 18, 03:45pm until August 18, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 18, 03:45pm until August 18, 08:00pm

    NOW until 8:00pm Mon

    Heat Advisory

  • This Afternoon

    High: 94 °F

    Sunny

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly after 5am. Partly cloudy, with a low around 74. South wind 3 to 6 mph.

    Low: 74 °F

    Chance
    T-storms

  • Tuesday

    Tuesday: A chance of showers and thunderstorms before 9am, then a slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 91. Light and variable wind becoming north 5 to 8 mph in the morning. Chance of precipitation is 30%.

    High: 91 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A chance of showers and thunderstorms before 4am, then a slight chance of showers. Partly cloudy, with a low around 72. North wind 3 to 7 mph. Chance of precipitation is 30%.

    Low: 72 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 85. North wind 6 to 10 mph.

    High: 85 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Wednesday Night

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

    Low: 65 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Thursday Night

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

    Low: 66 °F

    Mostly Clear

Detailed Forecast

This Afternoon
Sunny, with a high near 94. Heat index values as high as 105. South wind around 7 mph.
Tonight
A 30 percent chance of showers and thunderstorms, mainly after 5am. Partly cloudy, with a low around 74. South wind 3 to 6 mph.
Tuesday
A chance of showers and thunderstorms before 9am, then a slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 91. Light and variable wind becoming north 5 to 8 mph in the morning. Chance of precipitation is 30%.
Tuesday Night
A chance of showers and thunderstorms before 4am, then a slight chance of showers. Partly cloudy, with a low around 72. North wind 3 to 7 mph. Chance of precipitation is 30%.
Wednesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 85. North wind 6 to 10 mph.
Wednesday Night
Mostly clear, with a low around 65.
Thursday
Mostly sunny, with a high near 84.
Thursday Night
Mostly clear, with a low around 66.
Friday
Sunny, with a high near 86.
Friday Night
Mostly clear, with a low around 67.
Saturday
Sunny, with a high near 85.
Saturday Night
Mostly clear, with a low around 61.
Sunday
Sunny, with a high near 78.
Sunday Night
Partly cloudy, with a low around 57.
Monday
Mostly sunny, with a high near 76.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles SSW Dow IL
 39°N 90.33°W (Elev. 597 ft)
Last Update:
2:01 pm CDT Aug 18, 2025
Forecast Valid:
3pm CDT Aug 18, 2025-6pm CDT Aug 25, 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