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

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

Lat: 38.93°NLon: 90.43°WElev: 436ft.

Fair

86°F

30°C

Humidity 36%
Wind Speed S 8 mph
Barometer 29.93 in (1013.1 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 11 Oct 4:54 pm CDT
Extended Forecast for

Grafton IL

  • Tonight

    Tonight: Partly cloudy, with a low around 65. Southeast wind 5 to 7 mph.

    Low: 65 °F

    Partly Cloudy

  • Columbus Day

    Columbus Day: Sunny, with a high near 93. Southwest wind 7 to 14 mph, with gusts as high as 21 mph.

    High: 93 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 71. South wind around 10 mph.

    Low: 71 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 91. Southwest wind 8 to 10 mph.

    High: 91 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70. South wind 5 to 7 mph.

    Low: 70 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. High near 81. Chance of precipitation is 90%.

    High: 81 °F

    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Cloudy, with a low around 64. Chance of precipitation is 70%.

    Low: 64 °F

    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 76. Chance of precipitation is 90%.

    High: 76 °F

    Showers

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 54.

    Low: 54 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Partly cloudy, with a low around 65. Southeast wind 5 to 7 mph.
Columbus Day
Sunny, with a high near 93. Southwest wind 7 to 14 mph, with gusts as high as 21 mph.
Monday Night
Mostly clear, with a low around 71. South wind around 10 mph.
Tuesday
Sunny, with a high near 91. Southwest wind 8 to 10 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70. South wind 5 to 7 mph.
Wednesday
Showers and possibly a thunderstorm. High near 81. Chance of precipitation is 90%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Cloudy, with a low around 64. Chance of precipitation is 70%.
Thursday
Showers and possibly a thunderstorm. High near 76. Chance of precipitation is 90%.
Thursday Night
A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 54.
Friday
Partly sunny, with a high near 66. Breezy.
Friday Night
Partly cloudy, with a low around 41.
Saturday
Sunny, with a high near 60.
Saturday Night
Clear, with a low around 39.
Sunday
Sunny, with a high near 67.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Grafton IL
 38.98°N 90.42°W (Elev. 673 ft)
Last Update:
3:26 pm CDT Oct 11, 2026
Forecast Valid:
5pm CDT Oct 11, 2026-6pm CDT Oct 18, 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