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

Dangerous Heat over the South-Central and Southwest U.S. Through Next Week

Dangerous heat persists across the Desert Southwest through this weekend and across the Southern Plains and Lower Mississippi Valley through at least the middle of next week. Numerous daily record high temperatures are expected through at least Tuesday for much of Texas and Oklahoma as well as portions of Louisiana, New Mexico, and Arizona. Read More >

Current conditions at

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Fair

72°F

22°C

Humidity 83%
Wind Speed NW 5 mph
Barometer 30.03 in
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 22 Aug 8:55 pm CDT
Extended Forecast for

Williamson IL

  • Tonight

    Tonight: Mostly clear, with a low around 62. Light north wind.

    Low: 62 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 82. Calm wind becoming northwest 5 to 7 mph in the afternoon.

    High: 82 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 60. Light and variable wind.

    Low: 60 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 82. Light east wind.

    High: 82 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 63. Light east wind.

    Low: 63 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 66.

    Low: 66 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 67.

    Low: 67 °F

    Slight Chance
    T-storms

Detailed Forecast

Tonight
Mostly clear, with a low around 62. Light north wind.
Sunday
Sunny, with a high near 82. Calm wind becoming northwest 5 to 7 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 60. Light and variable wind.
Monday
Mostly sunny, with a high near 82. Light east wind.
Monday Night
Partly cloudy, with a low around 63. Light east wind.
Tuesday
Mostly sunny, with a high near 84.
Tuesday Night
Partly cloudy, with a low around 66.
Wednesday
Mostly sunny, with a high near 86.
Wednesday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 67.
Thursday
Sunny, with a high near 86.
Thursday Night
Mostly clear, with a low around 65.
Friday
Sunny, with a high near 85.
Friday Night
Partly cloudy, with a low around 66.
Saturday
Mostly sunny, with a high near 86.
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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:
5:56 pm CDT Aug 22, 2026
Forecast Valid:
9pm CDT Aug 22, 2026-6pm CDT Aug 29, 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