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

Hazardous Weather Conditions

Current conditions at

Marion - Williamson County Regional Airport (KMWA)

Lat: 37.77°NLon: 89.01°WElev: 486ft.

Fair

84°F

29°C

Humidity 66%
Wind Speed SW 1 mph
Barometer 29.98 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index89°F (32°C)
Last update 3 Sep 10:15 pm CDT
Extended Forecast for

Royalton IL

Extreme Heat Warning September 3, 10:25pm until September 5, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning September 3, 10:25pm until September 5, 08:00pm

    NOW until 8:00pm Sat

    Extreme Heat Warning

  • Tonight

    Low: 75 °F

    Clear

  • Friday

    Friday: Sunny and hot, with a high near 100. Heat index values as high as 108. Calm wind becoming west southwest around 5 mph in the afternoon.

    High: 100 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 75. Calm wind.

    Low: 75 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 100. Heat index values as high as 107. Calm wind becoming northwest around 6 mph in the afternoon.

    High: 100 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 72. Calm wind.

    Low: 72 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 95. Light northeast wind increasing to 5 to 10 mph in the morning.

    High: 95 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 67. East northeast wind 5 to 11 mph.

    Low: 67 °F

    Mostly Clear

  • Labor Day

    Labor Day: Sunny, with a high near 93. East northeast wind 5 to 8 mph.

    High: 93 °F

    Sunny

Detailed Forecast

Tonight
Clear, with a low around 75. Calm wind.
Friday
Sunny and hot, with a high near 100. Heat index values as high as 108. Calm wind becoming west southwest around 5 mph in the afternoon.
Friday Night
Mostly clear, with a low around 75. Calm wind.
Saturday
Sunny and hot, with a high near 100. Heat index values as high as 107. Calm wind becoming northwest around 6 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 72. Calm wind.
Sunday
Sunny, with a high near 95. Light northeast wind increasing to 5 to 10 mph in the morning.
Sunday Night
Mostly clear, with a low around 67. East northeast wind 5 to 11 mph.
Labor Day
Sunny, with a high near 93. East northeast wind 5 to 8 mph.
Monday Night
Mostly clear, with a low around 68. East wind around 6 mph becoming calm in the evening.
Tuesday
Sunny, with a high near 96. Calm wind becoming south 5 to 8 mph in the morning.
Tuesday Night
Mostly clear, with a low around 74. South southeast wind 6 to 8 mph.
Wednesday
Sunny and hot, with a high near 98. South southwest wind 9 to 11 mph.
Wednesday Night
Mostly clear, with a low around 75. South southwest wind around 9 mph.
Thursday
A slight chance of showers. Mostly sunny, with a high near 94. Southwest wind 9 to 11 mph.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Royalton IL
 37.87°N 89.11°W
Last Update:
10:11 pm CDT Sep 3, 2026
Forecast Valid:
10pm CDT Sep 3, 2026-6pm CDT Sep 10, 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