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.

Fog/Mist

67°F

19°C

Humidity 97%
Wind Speed Calm
Barometer 30.00 in (1015.4 mb)
Dewpoint 66°F (19°C)
Visibility 5.00 mi
Last update 20 Jun 3:54 am CDT
Extended Forecast for

Grafton IL

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

  • Today

    Today: Sunny, with a high near 91. South wind 5 to 11 mph.

    High: 91 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 76. South wind 9 to 11 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 95. Heat index values as high as 104. Southwest wind 10 to 15 mph, with gusts as high as 24 mph.

    High: 95 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 77. South wind 8 to 11 mph, with gusts as high as 20 mph.

    Low: 77 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 95. Southwest wind 8 to 10 mph, with gusts as high as 20 mph.

    High: 95 °F

    Sunny

  • Sunday Night

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

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 94.

    High: 94 °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

Detailed Forecast

Today
Sunny, with a high near 91. South wind 5 to 11 mph.
Tonight
Clear, with a low around 76. South wind 9 to 11 mph, with gusts as high as 20 mph.
Saturday
Sunny, with a high near 95. Heat index values as high as 104. Southwest wind 10 to 15 mph, with gusts as high as 24 mph.
Saturday Night
Mostly clear, with a low around 77. South wind 8 to 11 mph, with gusts as high as 20 mph.
Sunday
Sunny, with a high near 95. Southwest wind 8 to 10 mph, with gusts as high as 20 mph.
Sunday Night
Mostly clear, with a low around 76.
Monday
Sunny, with a high near 94.
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. Sunny, with a high near 93.
Wednesday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 75.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91.
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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:
3:36 am CDT Jun 20, 2025
Forecast Valid:
4am CDT Jun 20, 2025-6pm CDT Jun 26, 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