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

57°F

14°C

Humidity 96%
Wind Speed Calm
Barometer 30.02 in (1016.5 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 11 Oct 8:54 am CDT
Extended Forecast for

Grafton IL

  • Today

    Today: Sunny, with a high near 88. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 88 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 65. Southeast wind around 6 mph becoming southwest after midnight.

    Low: 65 °F

    Partly Cloudy

  • Columbus Day

    Columbus Day: Sunny, with a high near 93. Southwest wind 7 to 15 mph, with gusts as high as 22 mph.

    High: 93 °F

    Sunny

  • Monday Night

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

    Low: 71 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 94. Southwest wind 8 to 10 mph.

    High: 94 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 69.

    Low: 69 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. High near 82. Chance of precipitation is 80%.

    High: 82 °F

    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.

    Low: 62 °F

    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 77. Chance of precipitation is 80%.

    High: 77 °F

    Showers

Detailed Forecast

Today
Sunny, with a high near 88. Calm wind becoming southwest around 5 mph in the afternoon.
Tonight
Partly cloudy, with a low around 65. Southeast wind around 6 mph becoming southwest after midnight.
Columbus Day
Sunny, with a high near 93. Southwest wind 7 to 15 mph, with gusts as high as 22 mph.
Monday Night
Clear, with a low around 71. South wind around 10 mph.
Tuesday
Sunny, with a high near 94. Southwest wind 8 to 10 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 69.
Wednesday
Showers and possibly a thunderstorm. High near 82. Chance of precipitation is 80%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.
Thursday
Showers and possibly a thunderstorm. High near 77. Chance of precipitation is 80%.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 54.
Friday
A 20 percent chance of showers. Partly sunny, with a high near 67. Breezy.
Friday Night
Partly cloudy, with a low around 43.
Saturday
Sunny, with a high near 61.
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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:
9:01 am CDT Oct 11, 2026
Forecast Valid:
9am CDT Oct 11, 2026-6pm CDT Oct 17, 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