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

38°F

3°C

Humidity 67%
Wind Speed E 7 mph
Barometer 30.10 in
Dewpoint 28°F (-2°C)
Visibility 10.00 mi
Wind Chill33°F (1°C)
Last update 14 Mar 4:55 am CDT
Extended Forecast for

Williamson IL

  • Today

    Today: Mostly sunny, with a high near 59. East wind 7 to 15 mph becoming southeast in the afternoon. Winds could gust as high as 22 mph.

    High: 59 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 51. Southeast wind 11 to 17 mph, with gusts as high as 26 mph.

    Low: 51 °F

    Partly Cloudy

  • Sunday

    Sunday: A chance of rain and thunderstorms, then rain after 1pm. High near 66. Breezy, with a south wind 22 to 29 mph, with gusts as high as 40 mph. Chance of precipitation is 90%.

    High: 66 °F

    Breezy.
    Chance Rain
    then Rain

  • Sunday Night

    Sunday Night: Rain before 10pm, then snow, possibly mixed with rain between 10pm and 1am, then a chance of snow after 1am. Low around 19. Breezy, with a southwest wind 23 to 28 mph becoming west in the evening. Winds could gust as high as 41 mph. Chance of precipitation is 90%. New snow accumulation of less than one inch possible.

    Low: 19 °F

    Rain/Snow and
    Breezy

  • Monday

    Monday: A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 25. Blustery, with a northwest wind 26 to 28 mph, with gusts as high as 40 mph.

    High: 25 °F

    Chance Snow
    and Blustery

  • Monday Night

    Monday Night: Partly cloudy, with a low around 11. Blustery.

    Low: 11 °F

    Mostly Cloudy
    and Blustery
    then Mostly
    Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 32.

    High: 32 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A 40 percent chance of snow. Mostly cloudy, with a low around 27.

    Low: 27 °F

    Chance Snow

  • Wednesday

    Wednesday: Partly sunny, with a high near 60.

    High: 60 °F

    Partly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 59. East wind 7 to 15 mph becoming southeast in the afternoon. Winds could gust as high as 22 mph.
Tonight
Partly cloudy, with a low around 51. Southeast wind 11 to 17 mph, with gusts as high as 26 mph.
Sunday
A chance of rain and thunderstorms, then rain after 1pm. High near 66. Breezy, with a south wind 22 to 29 mph, with gusts as high as 40 mph. Chance of precipitation is 90%.
Sunday Night
Rain before 10pm, then snow, possibly mixed with rain between 10pm and 1am, then a chance of snow after 1am. Low around 19. Breezy, with a southwest wind 23 to 28 mph becoming west in the evening. Winds could gust as high as 41 mph. Chance of precipitation is 90%. New snow accumulation of less than one inch possible.
Monday
A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 25. Blustery, with a northwest wind 26 to 28 mph, with gusts as high as 40 mph.
Monday Night
Partly cloudy, with a low around 11. Blustery.
Tuesday
Mostly sunny, with a high near 32.
Tuesday Night
A 40 percent chance of snow. Mostly cloudy, with a low around 27.
Wednesday
Partly sunny, with a high near 60.
Wednesday Night
Mostly clear, with a low around 37.
Thursday
Sunny, with a high near 67.
Thursday Night
Partly cloudy, with a low around 45.
Friday
Sunny, with a high near 67.
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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:
4:41 am CDT Mar 14, 2026
Forecast Valid:
5am CDT Mar 14, 2026-6pm CDT Mar 20, 2026
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation