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.

Fair

64°F

18°C

Humidity 73%
Wind Speed Vrbl 3 mph
Barometer 30.05 in
Dewpoint 55°F (13°C)
Visibility 10.00 mi
Last update 11 Oct 9:50 am CDT
Extended Forecast for

Williamson IL

  • Today

    Today: Sunny, with a high near 87. Light and variable wind.

    High: 87 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 61. Light south wind.

    Low: 61 °F

    Mostly Clear

  • Columbus Day

    Columbus Day: Partly sunny, then gradually becoming sunny, with a high near 93. Southwest wind 5 to 13 mph.

    High: 93 °F

    Becoming
    Sunny

  • Monday Night

    Monday Night: Clear, with a low around 68. Southwest wind 7 to 9 mph.

    Low: 68 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 93. West wind 7 to 10 mph.

    High: 93 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 67.

    Low: 67 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 82. Chance of precipitation is 70%.

    High: 82 °F

    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A chance of showers, with thunderstorms also possible after 1am. Mostly cloudy, with a low around 60. Chance of precipitation is 50%.

    Low: 60 °F

    Chance
    Showers

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 77. Chance of precipitation is 70%.

    High: 77 °F

    Showers
    Likely

Detailed Forecast

Today
Sunny, with a high near 87. Light and variable wind.
Tonight
Mostly clear, with a low around 61. Light south wind.
Columbus Day
Partly sunny, then gradually becoming sunny, with a high near 93. Southwest wind 5 to 13 mph.
Monday Night
Clear, with a low around 68. Southwest wind 7 to 9 mph.
Tuesday
Sunny, with a high near 93. West wind 7 to 10 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 67.
Wednesday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 82. Chance of precipitation is 70%.
Wednesday Night
A chance of showers, with thunderstorms also possible after 1am. Mostly cloudy, with a low around 60. Chance of precipitation is 50%.
Thursday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 77. Chance of precipitation is 70%.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 52.
Friday
Partly sunny, with a high near 67. Breezy.
Friday Night
Partly cloudy, with a low around 40.
Saturday
Mostly sunny, with a high near 60.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Williamson IL
 38.98°N 89.76°W (Elev. 597 ft)
Last Update:
9:01 am CDT Oct 11, 2026
Forecast Valid:
10am CDT Oct 11, 2026-6pm CDT Oct 17, 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