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.

Overcast

82°F

28°C

Humidity 67%
Wind Speed NW 6 mph
Barometer 29.52 in (999.0 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 17 Jun 9:54 pm CDT
Extended Forecast for

3 Miles WNW Grafton IL

  • Tonight

    Tonight: Isolated showers and thunderstorms before 11pm. Partly cloudy, with a low around 68. West wind 6 to 9 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

    Low: 68 °F

    Isolated
    T-storms then
    Partly Cloudy

  • Thursday

    Thursday: Increasing clouds, with a high near 77. Northwest wind 6 to 8 mph.

    High: 77 °F

    Increasing
    Clouds

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 59. Northwest wind around 5 mph becoming calm in the evening.

    Low: 59 °F

    Mostly Clear

  • Juneteenth

    Juneteenth: Mostly sunny, with a high near 82. Light northwest wind.

    High: 82 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 64. Light and variable wind.

    Low: 64 °F

    Partly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 84.

    High: 84 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 67.

    Low: 67 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Sunday

    Sunday: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 82. Chance of precipitation is 80%.

    High: 82 °F

    Heavy Rain

  • Sunday Night

    Sunday Night: Showers and possibly a thunderstorm before 1am, then a chance of showers. Low around 64. Chance of precipitation is 80%.

    Low: 64 °F

    Showers

Detailed Forecast

Tonight
Isolated showers and thunderstorms before 11pm. Partly cloudy, with a low around 68. West wind 6 to 9 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.
Thursday
Increasing clouds, with a high near 77. Northwest wind 6 to 8 mph.
Thursday Night
Mostly clear, with a low around 59. Northwest wind around 5 mph becoming calm in the evening.
Juneteenth
Mostly sunny, with a high near 82. Light northwest wind.
Friday Night
Partly cloudy, with a low around 64. Light and variable wind.
Saturday
Partly sunny, with a high near 84.
Saturday Night
A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 67.
Sunday
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 82. Chance of precipitation is 80%.
Sunday Night
Showers and possibly a thunderstorm before 1am, then a chance of showers. Low around 64. Chance of precipitation is 80%.
Monday
Partly sunny, with a high near 78.
Monday Night
Partly cloudy, with a low around 61.
Tuesday
Mostly sunny, with a high near 80.
Tuesday Night
Partly cloudy, with a low around 62.
Wednesday
Mostly sunny, with a high near 83.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles WNW Grafton IL
 39°N 90.47°W (Elev. 801 ft)
Last Update:
10:31 pm CDT Jun 17, 2026
Forecast Valid:
10pm CDT Jun 17, 2026-6pm CDT Jun 24, 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