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

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Overcast

86°F

30°C

Humidity 62%
Wind Speed Vrbl 6 mph
Barometer 30.01 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index92°F (33°C)
Last update 8 Jul 2:45 pm CDT
Extended Forecast for

Glen Carbon IL

  • This Afternoon

    This Afternoon: Isolated showers and thunderstorms. Partly sunny, with a high near 89. South wind around 5 mph becoming calm. Chance of precipitation is 20%.

    High: 89 °F

    Isolated
    T-storms

  • Tonight

    Tonight: Isolated showers and thunderstorms before 8pm. Mostly cloudy, then gradually becoming clear, with a low around 72. Light south wind. Chance of precipitation is 20%.

    Low: 72 °F

    Isolated
    T-storms then
    Mostly Clear

  • Thursday

    Thursday: Showers and thunderstorms likely, mainly after 5pm. Mostly sunny, with a high near 93. Heat index values as high as 101. Southwest wind 3 to 7 mph. Chance of precipitation is 60%.

    High: 93 °F

    Sunny then
    T-storms
    Likely

  • Thursday Night

    Thursday Night: Scattered showers and thunderstorms, mainly before 4am. Mostly cloudy, with a low around 75. Southwest wind around 6 mph becoming light and variable. Chance of precipitation is 50%.

    Low: 75 °F

    Scattered
    T-storms

  • Friday

    Friday: Showers and thunderstorms likely, mainly after 1pm. Partly sunny, with a high near 89. West wind around 6 mph. Chance of precipitation is 70%.

    High: 89 °F

    Chance
    Showers then
    T-storms
    Likely

  • Friday Night

    Friday Night: Showers and thunderstorms likely before 1am, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 72. Chance of precipitation is 70%.

    Low: 72 °F

    T-storms
    Likely

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 87.

    High: 87 °F

    Chance
    Showers then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before 1am, then a slight chance of showers. Partly cloudy, with a low around 70. Chance of precipitation is 40%.

    Low: 70 °F

    Chance
    Showers

  • Sunday

    Sunday: A 20 percent chance of showers. Mostly sunny, with a high near 87.

    High: 87 °F

    Slight Chance
    Showers

Detailed Forecast

This Afternoon
Isolated showers and thunderstorms. Partly sunny, with a high near 89. South wind around 5 mph becoming calm. Chance of precipitation is 20%.
Tonight
Isolated showers and thunderstorms before 8pm. Mostly cloudy, then gradually becoming clear, with a low around 72. Light south wind. Chance of precipitation is 20%.
Thursday
Showers and thunderstorms likely, mainly after 5pm. Mostly sunny, with a high near 93. Heat index values as high as 101. Southwest wind 3 to 7 mph. Chance of precipitation is 60%.
Thursday Night
Scattered showers and thunderstorms, mainly before 4am. Mostly cloudy, with a low around 75. Southwest wind around 6 mph becoming light and variable. Chance of precipitation is 50%.
Friday
Showers and thunderstorms likely, mainly after 1pm. Partly sunny, with a high near 89. West wind around 6 mph. Chance of precipitation is 70%.
Friday Night
Showers and thunderstorms likely before 1am, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 72. Chance of precipitation is 70%.
Saturday
A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 87.
Saturday Night
A chance of showers and thunderstorms before 1am, then a slight chance of showers. Partly cloudy, with a low around 70. Chance of precipitation is 40%.
Sunday
A 20 percent chance of showers. Mostly sunny, with a high near 87.
Sunday Night
Mostly clear, with a low around 69.
Monday
Sunny, with a high near 89.
Monday Night
Mostly clear, with a low around 71.
Tuesday
Sunny, with a high near 91.
Tuesday Night
Clear, with a low around 72.
Wednesday
Sunny, with a high near 92.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Glen Carbon IL
 38.75°N 89.97°W (Elev. 499 ft)
Last Update:
2:26 pm CDT Jul 8, 2026
Forecast Valid:
3pm CDT Jul 8, 2026-6pm CDT Jul 15, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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