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.

Partly Cloudy

71°F

22°C

Humidity 68%
Wind Speed NW 7 mph
Barometer 30.06 in (1017.5 mb)
Dewpoint 60°F (16°C)
Visibility 10.00 mi
Last update 22 Jun 6:54 pm CDT
Extended Forecast for

4 Miles S Portage Des Sioux MO

  • Tonight

    Tonight: Patchy fog after midnight. Otherwise, mostly cloudy during the early evening, then gradual clearing, with a low around 60. North wind 5 to 8 mph becoming calm in the evening.

    Low: 60 °F

    Mostly Cloudy
    then Patchy
    Fog

  • Tuesday

    Tuesday: Patchy fog before 8am. Otherwise, sunny, with a high near 82. Calm wind becoming northeast around 5 mph in the afternoon.

    High: 82 °F

    Patchy Fog
    then Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 1am. Increasing clouds, with a low around 64. Southeast wind 3 to 6 mph.

    Low: 64 °F

    Mostly Clear
    then Slight
    Chance
    Showers

  • Wednesday

    Wednesday: A chance of showers, with thunderstorms also possible after 10am. Partly sunny, with a high near 84. Southeast wind 5 to 7 mph becoming southwest in the afternoon. Chance of precipitation is 50%.

    High: 84 °F

    Chance
    Showers then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. West wind around 5 mph becoming calm in the evening.

    Low: 67 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 85.

    High: 85 °F

    Partly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.

    Low: 67 °F

    Chance
    T-storms then
    Showers
    Likely

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 1pm, then showers and thunderstorms likely after 1pm. Mostly cloudy, with a high near 83. Chance of precipitation is 70%.

    High: 83 °F

    Showers
    Likely then
    T-storms
    Likely

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 69. Chance of precipitation is 60%.

    Low: 69 °F

    Showers
    Likely

Detailed Forecast

Tonight
Patchy fog after midnight. Otherwise, mostly cloudy during the early evening, then gradual clearing, with a low around 60. North wind 5 to 8 mph becoming calm in the evening.
Tuesday
Patchy fog before 8am. Otherwise, sunny, with a high near 82. Calm wind becoming northeast around 5 mph in the afternoon.
Tuesday Night
A 20 percent chance of showers after 1am. Increasing clouds, with a low around 64. Southeast wind 3 to 6 mph.
Wednesday
A chance of showers, with thunderstorms also possible after 10am. Partly sunny, with a high near 84. Southeast wind 5 to 7 mph becoming southwest in the afternoon. Chance of precipitation is 50%.
Wednesday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. West wind around 5 mph becoming calm in the evening.
Thursday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 85.
Thursday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.
Friday
Showers likely and possibly a thunderstorm before 1pm, then showers and thunderstorms likely after 1pm. Mostly cloudy, with a high near 83. Chance of precipitation is 70%.
Friday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 69. Chance of precipitation is 60%.
Saturday
A 30 percent chance of showers and thunderstorms, mainly before 1pm. Partly sunny, with a high near 88.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 94.
Sunday Night
Mostly clear, with a low around 77.
Monday
Sunny, with a high near 95.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles S Portage Des Sioux MO
 38.87°N 90.33°W (Elev. 456 ft)
Last Update:
6:16 pm CDT Jun 22, 2026
Forecast Valid:
7pm CDT Jun 22, 2026-6pm CDT Jun 29, 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