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.

Partly Cloudy

82°F

28°C

Humidity 55%
Wind Speed SW 8 mph
Barometer 30.01 in
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 24 Jun 3:50 pm CDT
Extended Forecast for

Williamson IL

Flood Watch June 25, 01:00pm until June 26, 07:00am
Click here for hazard details and duration
Flood Watch

  • This Afternoon

    This Afternoon: A 30 percent chance of showers and thunderstorms, mainly after 5pm. Partly sunny, with a high near 81. Southwest wind around 6 mph.

    High: 81 °F

    Chance
    T-storms

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 65. South wind around 5 mph becoming calm in the evening.

    Low: 65 °F

    Chance
    T-storms

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms, mainly after 10am. Partly sunny, with a high near 83. Light and variable wind.

    High: 83 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2am. Some of the storms could produce heavy rainfall. Low around 67. Light and variable wind. Chance of precipitation is 80%.

    Low: 67 °F

    Heavy Rain

  • Friday

    Friday: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 80. Southeast wind 5 to 8 mph becoming southwest in the afternoon. Chance of precipitation is 90%.

    High: 80 °F

    Heavy Rain

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.

    Low: 67 °F

    Showers
    Likely

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.

    High: 85 °F

    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 71.

    Low: 71 °F

    Slight Chance
    T-storms

  • Sunday

    Sunday: Sunny, with a high near 93.

    High: 93 °F

    Sunny

Detailed Forecast

This Afternoon
A 30 percent chance of showers and thunderstorms, mainly after 5pm. Partly sunny, with a high near 81. Southwest wind around 6 mph.
Tonight
A 30 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 65. South wind around 5 mph becoming calm in the evening.
Thursday
A 40 percent chance of showers and thunderstorms, mainly after 10am. Partly sunny, with a high near 83. Light and variable wind.
Thursday Night
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2am. Some of the storms could produce heavy rainfall. Low around 67. Light and variable wind. Chance of precipitation is 80%.
Friday
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 80. Southeast wind 5 to 8 mph becoming southwest in the afternoon. Chance of precipitation is 90%.
Friday Night
Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.
Saturday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
Saturday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 71.
Sunday
Sunny, with a high near 93.
Sunday Night
Mostly clear, with a low around 73.
Monday
Sunny, with a high near 94.
Monday Night
Mostly clear, with a low around 74.
Tuesday
Sunny, with a high near 95.
Tuesday Night
Mostly clear, with a low around 74.
Wednesday
Sunny, with a high near 95.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Williamson IL
 38.98°N 89.76°W (Elev. 597 ft)
Last Update:
2:52 pm CDT Jun 24, 2026
Forecast Valid:
4pm CDT Jun 24, 2026-6pm CDT Jul 1, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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