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

90°F

32°C

Humidity 54%
Wind Speed SE 8 mph
Barometer 29.97 in (1014.4 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index96°F (36°C)
Last update 20 Jun 3:54 pm CDT
Extended Forecast for

Grafton IL

Extreme Heat Warning June 21, 12:00pm until June 24, 09:00pm
Click here for hazard details and duration
Extreme Heat Warning

  • Tonight

    Tonight: Clear, with a low around 76. South wind 7 to 13 mph, with gusts as high as 22 mph.

    Low: 76 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 96. Heat index values as high as 104. Southwest wind 9 to 16 mph, with gusts as high as 26 mph.

    High: 96 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 75. South wind 8 to 13 mph, with gusts as high as 22 mph.

    Low: 75 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 95. Heat index values as high as 102. Southwest wind 8 to 11 mph, with gusts as high as 20 mph.

    High: 95 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 77. South wind 7 to 10 mph.

    Low: 77 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 95.

    High: 95 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 76.

    Low: 76 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers before 1pm. Mostly sunny, with a high near 93.

    High: 93 °F

    Slight Chance
    Showers

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 76.

    Low: 76 °F

    Partly Cloudy

Detailed Forecast

Tonight
Clear, with a low around 76. South wind 7 to 13 mph, with gusts as high as 22 mph.
Saturday
Sunny, with a high near 96. Heat index values as high as 104. Southwest wind 9 to 16 mph, with gusts as high as 26 mph.
Saturday Night
Mostly clear, with a low around 75. South wind 8 to 13 mph, with gusts as high as 22 mph.
Sunday
Sunny, with a high near 95. Heat index values as high as 102. Southwest wind 8 to 11 mph, with gusts as high as 20 mph.
Sunday Night
Clear, with a low around 77. South wind 7 to 10 mph.
Monday
Sunny, with a high near 95.
Monday Night
Partly cloudy, with a low around 76.
Tuesday
A 20 percent chance of showers before 1pm. Mostly sunny, with a high near 93.
Tuesday Night
Partly cloudy, with a low around 76.
Wednesday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 93.
Wednesday Night
Partly cloudy, with a low around 75.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91.
Thursday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73.
Friday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Grafton IL
 38.98°N 90.42°W (Elev. 673 ft)
Last Update:
2:21 pm CDT Jun 20, 2025
Forecast Valid:
4pm CDT Jun 20, 2025-6pm CDT Jun 27, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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