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

St. Louis Lambert International Airport (KSTL)

Lat: 38.75°NLon: 90.37°WElev: 604ft.

Mostly Cloudy

75°F

24°C

Humidity 74%
Wind Speed Calm
Barometer 29.90 in (1011.6 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 22 Sep 1:51 pm CDT
Extended Forecast for

Saint Charles MO

  • This Afternoon

    This Afternoon: Partly sunny, with a high near 78. South wind 3 to 5 mph.

    High: 78 °F

    Partly Sunny

  • Tonight

    Tonight: Patchy fog after 3am. Otherwise, partly cloudy, with a low around 65. Light south wind.

    Low: 65 °F

    Partly Cloudy
    then Patchy
    Fog

  • Tuesday

    Tuesday: Scattered showers and thunderstorms, then showers likely and possibly a thunderstorm after 4pm. Areas of fog before 9am. Otherwise, mostly cloudy, with a high near 80. Calm wind becoming southeast around 6 mph in the morning. Chance of precipitation is 60%.

    High: 80 °F

    Areas Fog
    then Showers
    Likely

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm before 1am, then showers likely. Low around 66. Light and variable wind becoming northeast around 6 mph after midnight. Chance of precipitation is 80%.

    Low: 66 °F

    Showers

  • Wednesday

    Wednesday: Showers likely, with thunderstorms also possible after 1pm. Mostly cloudy, with a high near 75. North wind 6 to 9 mph. Chance of precipitation is 60%.

    High: 75 °F

    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 61. Chance of precipitation is 30%.

    Low: 61 °F

    Chance
    T-storms then
    Chance
    Showers

  • Thursday

    Thursday: A 30 percent chance of showers, mainly after 1pm. Mostly sunny, with a high near 75.

    High: 75 °F

    Chance
    Showers

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 58.

    Low: 58 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 80.

    High: 80 °F

    Sunny

Detailed Forecast

This Afternoon
Partly sunny, with a high near 78. South wind 3 to 5 mph.
Tonight
Patchy fog after 3am. Otherwise, partly cloudy, with a low around 65. Light south wind.
Tuesday
Scattered showers and thunderstorms, then showers likely and possibly a thunderstorm after 4pm. Areas of fog before 9am. Otherwise, mostly cloudy, with a high near 80. Calm wind becoming southeast around 6 mph in the morning. Chance of precipitation is 60%.
Tuesday Night
Showers and possibly a thunderstorm before 1am, then showers likely. Low around 66. Light and variable wind becoming northeast around 6 mph after midnight. Chance of precipitation is 80%.
Wednesday
Showers likely, with thunderstorms also possible after 1pm. Mostly cloudy, with a high near 75. North wind 6 to 9 mph. Chance of precipitation is 60%.
Wednesday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 61. Chance of precipitation is 30%.
Thursday
A 30 percent chance of showers, mainly after 1pm. Mostly sunny, with a high near 75.
Thursday Night
Mostly clear, with a low around 58.
Friday
Sunny, with a high near 80.
Friday Night
Clear, with a low around 58.
Saturday
Sunny, with a high near 83.
Saturday Night
Mostly clear, with a low around 60.
Sunday
Sunny, with a high near 84.
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ABOUT THIS FORECAST

 
Point Forecast:
Saint Charles MO
 38.78°N 90.51°W (Elev. 597 ft)
Last Update:
2:21 pm CDT Sep 22, 2025
Forecast Valid:
2pm CDT Sep 22, 2025-6pm CDT Sep 28, 2025
 
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