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

32°F

0°C

Humidity 35%
Wind Speed NW 18 G 28 mph
Barometer 30.46 in (1031.9 mb)
Dewpoint 7°F (-14°C)
Visibility 10.00 mi
Wind Chill21°F (-6°C)
Last update 22 Feb 4:54 pm CST
Extended Forecast for

Grafton IL

  • Tonight

    Tonight: Increasing clouds, with a low around 14. Northwest wind around 16 mph, with gusts as high as 29 mph.

    Low: 14 °F

    Increasing
    Clouds

  • Monday

    Monday: Sunny, with a high near 32. Northwest wind 7 to 15 mph, with gusts as high as 24 mph.

    High: 32 °F

    Sunny

  • Monday Night

    Monday Night: Increasing clouds, with a low around 21. Calm wind becoming south 5 to 9 mph after midnight.

    Low: 21 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 54. South wind 10 to 14 mph, with gusts as high as 26 mph.

    High: 54 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 33. Southwest wind 5 to 10 mph becoming light and variable after midnight.

    Low: 33 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 53.

    High: 53 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Rain likely. Mostly cloudy, with a low around 35. Chance of precipitation is 60%.

    Low: 35 °F

    Rain Likely

  • Thursday

    Thursday: A 20 percent chance of rain before noon. Mostly sunny, with a high near 51.

    High: 51 °F

    Slight Chance
    Rain then
    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 30.

    Low: 30 °F

    Mostly Clear

Detailed Forecast

Tonight
Increasing clouds, with a low around 14. Northwest wind around 16 mph, with gusts as high as 29 mph.
Monday
Sunny, with a high near 32. Northwest wind 7 to 15 mph, with gusts as high as 24 mph.
Monday Night
Increasing clouds, with a low around 21. Calm wind becoming south 5 to 9 mph after midnight.
Tuesday
Mostly cloudy, with a high near 54. South wind 10 to 14 mph, with gusts as high as 26 mph.
Tuesday Night
Mostly cloudy, with a low around 33. Southwest wind 5 to 10 mph becoming light and variable after midnight.
Wednesday
Mostly sunny, with a high near 53.
Wednesday Night
Rain likely. Mostly cloudy, with a low around 35. Chance of precipitation is 60%.
Thursday
A 20 percent chance of rain before noon. Mostly sunny, with a high near 51.
Thursday Night
Mostly clear, with a low around 30.
Friday
Sunny, with a high near 64.
Friday Night
Mostly clear, with a low around 39.
Saturday
Sunny, with a high near 62.
Saturday Night
Partly cloudy, with a low around 31.
Sunday
A slight chance of rain and snow. Partly sunny, with a high near 49. Chance of precipitation is 20%.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Grafton IL
 38.98°N 90.44°W (Elev. 515 ft)
Last Update:
3:11 pm CST Feb 22, 2026
Forecast Valid:
5pm CST Feb 22, 2026-6pm CST Mar 1, 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