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

Hazardous Weather Conditions

Current conditions at

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Fair

82°F

28°C

Humidity 55%
Wind Speed S 20 G 31 mph
Barometer 29.82 in
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 14 Apr 6:50 pm CDT
Extended Forecast for

Williamson IL

  • Tonight

    Tonight: Isolated showers and thunderstorms after 2am. Increasing clouds, with a low around 67. Southwest wind 10 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.

    Low: 67 °F

    Partly Cloudy
    then Isolated
    T-storms

  • Wednesday

    Wednesday: Showers and thunderstorms likely, mainly after 5pm. Mostly cloudy, with a high near 79. Southwest wind 9 to 16 mph, with gusts as high as 23 mph. Chance of precipitation is 60%.

    High: 79 °F

    T-storms
    Likely

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely before 1am, then showers and possibly a thunderstorm between 1am and 4am, then showers after 4am. Low around 62. Southwest wind 9 to 11 mph. Chance of precipitation is 90%.

    Low: 62 °F

    Showers
    Likely then
    Showers

  • Thursday

    Thursday: Showers likely, with thunderstorms also possible after 1pm. Mostly cloudy, then gradually becoming sunny, with a high near 77. West wind 8 to 13 mph. Chance of precipitation is 70%.

    High: 77 °F

    Showers
    Likely

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 58. West wind around 6 mph becoming light and variable after midnight.

    Low: 58 °F

    Mostly Clear

  • Friday

    Friday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 83.

    High: 83 °F

    Mostly Sunny
    then Chance
    T-storms

  • Friday Night

    Friday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 57. Chance of precipitation is 70%.

    Low: 57 °F

    Chance
    T-storms then
    Showers
    Likely

  • Saturday

    Saturday: Showers likely and possibly a thunderstorm before 1pm, then a chance of showers. Partly sunny, with a high near 69. Chance of precipitation is 60%.

    High: 69 °F

    Showers
    Likely

  • Saturday Night

    Saturday Night: A 20 percent chance of showers before 1am. Partly cloudy, with a low around 39.

    Low: 39 °F

    Slight Chance
    Showers

Detailed Forecast

Tonight
Isolated showers and thunderstorms after 2am. Increasing clouds, with a low around 67. Southwest wind 10 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.
Wednesday
Showers and thunderstorms likely, mainly after 5pm. Mostly cloudy, with a high near 79. Southwest wind 9 to 16 mph, with gusts as high as 23 mph. Chance of precipitation is 60%.
Wednesday Night
Showers and thunderstorms likely before 1am, then showers and possibly a thunderstorm between 1am and 4am, then showers after 4am. Low around 62. Southwest wind 9 to 11 mph. Chance of precipitation is 90%.
Thursday
Showers likely, with thunderstorms also possible after 1pm. Mostly cloudy, then gradually becoming sunny, with a high near 77. West wind 8 to 13 mph. Chance of precipitation is 70%.
Thursday Night
Mostly clear, with a low around 58. West wind around 6 mph becoming light and variable after midnight.
Friday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 83.
Friday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 57. Chance of precipitation is 70%.
Saturday
Showers likely and possibly a thunderstorm before 1pm, then a chance of showers. Partly sunny, with a high near 69. Chance of precipitation is 60%.
Saturday Night
A 20 percent chance of showers before 1am. Partly cloudy, with a low around 39.
Sunday
Sunny, with a high near 59.
Sunday Night
Clear, with a low around 37.
Monday
Sunny, with a high near 65.
Monday Night
Mostly clear, with a low around 44.
Tuesday
Sunny, with a high near 70.
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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:
6:46 pm CDT Apr 14, 2026
Forecast Valid:
7pm CDT Apr 14, 2026-6pm CDT Apr 21, 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