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

36°F

2°C

Humidity 52%
Wind Speed S 6 mph
Barometer 29.91 in
Dewpoint 19°F (-7°C)
Visibility 10.00 mi
Wind Chill31°F (-1°C)
Last update 5 Dec 3:50 pm CST
Extended Forecast for

Williamson IL

  • Tonight

    Tonight: Mostly cloudy, with a low around 26. South wind 5 to 7 mph becoming west after midnight.

    Low: 26 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 37. West wind around 5 mph becoming calm in the morning.

    High: 37 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: A chance of snow between 11pm and 3am, then a chance of rain after 3am. Mostly cloudy, with a low around 28. Southeast wind 3 to 6 mph. Chance of precipitation is 40%.

    Low: 28 °F

    Slight Chance
    Snow then
    Chance
    Rain/Snow

  • Sunday

    Sunday: A chance of rain before noon, then a slight chance of snow. Mostly cloudy, with a high near 37. South wind 6 to 11 mph becoming north in the afternoon. Chance of precipitation is 30%.

    High: 37 °F

    Chance Rain
    then Slight
    Chance Snow

  • Sunday Night

    Sunday Night: A 20 percent chance of snow before midnight. Mostly cloudy, with a low around 15. North wind 5 to 10 mph.

    Low: 15 °F

    Slight Chance
    Snow then
    Mostly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 29.

    High: 29 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 19.

    Low: 19 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 44.

    High: 44 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 34.

    Low: 34 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 26. South wind 5 to 7 mph becoming west after midnight.
Saturday
Partly sunny, with a high near 37. West wind around 5 mph becoming calm in the morning.
Saturday Night
A chance of snow between 11pm and 3am, then a chance of rain after 3am. Mostly cloudy, with a low around 28. Southeast wind 3 to 6 mph. Chance of precipitation is 40%.
Sunday
A chance of rain before noon, then a slight chance of snow. Mostly cloudy, with a high near 37. South wind 6 to 11 mph becoming north in the afternoon. Chance of precipitation is 30%.
Sunday Night
A 20 percent chance of snow before midnight. Mostly cloudy, with a low around 15. North wind 5 to 10 mph.
Monday
Mostly sunny, with a high near 29.
Monday Night
Partly cloudy, with a low around 19.
Tuesday
Mostly sunny, with a high near 44.
Tuesday Night
Mostly cloudy, with a low around 34.
Wednesday
A 30 percent chance of rain. Partly sunny, with a high near 44.
Wednesday Night
Mostly cloudy, with a low around 25.
Thursday
Mostly cloudy, with a high near 39.
Thursday Night
Mostly cloudy, with a low around 19.
Friday
Partly sunny, with a high near 29.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Williamson IL
 38.98°N 89.76°W (Elev. 597 ft)
Last Update:
3:16 pm CST Dec 5, 2025
Forecast Valid:
3pm CST Dec 5, 2025-6pm CST Dec 12, 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