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.

A Few Clouds

91°F

33°C

Humidity 46%
Wind Speed SW 9 mph
Barometer 30.06 in
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index95°F (35°C)
Last update 8 Sep 5:45 pm CDT
Extended Forecast for

Royalton IL

Heat Advisory September 9, 11:00am until September 9, 08:00pm
Click here for hazard details and duration
Heat Advisory

  • Tonight

    Tonight: Mostly clear, with a low around 74. Calm wind becoming south 5 to 8 mph after midnight.

    Low: 74 °F

    Mostly Clear

  • Wednesday

    Wednesday: A 30 percent chance of showers and thunderstorms, mainly after 3pm. Sunny and hot, with a high near 98. Heat index values as high as 106. South wind 8 to 13 mph becoming west in the afternoon. Winds could gust as high as 18 mph.

    High: 98 °F

    Sunny then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2am. Low around 71. South southwest wind around 5 mph becoming calm after midnight. Chance of precipitation is 80%.

    Low: 71 °F

    Chance
    T-storms then
    Showers

  • Thursday

    Thursday: Showers and possibly a thunderstorm before 10am, then showers between 10am and 1pm, then a chance of showers and thunderstorms after 1pm. High near 85. Calm wind becoming west 5 to 7 mph in the morning. Chance of precipitation is 90%.

    High: 85 °F

    Showers

  • Thursday Night

    Thursday Night: A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 1am. Mostly cloudy, with a low around 65. Calm wind. Chance of precipitation is 20%.

    Low: 65 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 88. Light and variable wind.

    High: 88 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 67. Calm wind.

    Low: 67 °F

    Mostly Clear

  • Saturday

    Saturday: A slight chance of showers after 1pm. Mostly sunny, with a high near 93. Calm wind becoming south southwest 5 to 7 mph in the morning.

    High: 93 °F

    Sunny then
    Slight Chance
    Showers

  • Saturday Night

    Saturday Night: A slight chance of showers. Partly cloudy, with a low around 69. Calm wind.

    Low: 69 °F

    Slight Chance
    Showers

Detailed Forecast

Tonight
Mostly clear, with a low around 74. Calm wind becoming south 5 to 8 mph after midnight.
Wednesday
A 30 percent chance of showers and thunderstorms, mainly after 3pm. Sunny and hot, with a high near 98. Heat index values as high as 106. South wind 8 to 13 mph becoming west in the afternoon. Winds could gust as high as 18 mph.
Wednesday Night
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2am. Low around 71. South southwest wind around 5 mph becoming calm after midnight. Chance of precipitation is 80%.
Thursday
Showers and possibly a thunderstorm before 10am, then showers between 10am and 1pm, then a chance of showers and thunderstorms after 1pm. High near 85. Calm wind becoming west 5 to 7 mph in the morning. Chance of precipitation is 90%.
Thursday Night
A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 1am. Mostly cloudy, with a low around 65. Calm wind. Chance of precipitation is 20%.
Friday
Mostly sunny, with a high near 88. Light and variable wind.
Friday Night
Mostly clear, with a low around 67. Calm wind.
Saturday
A slight chance of showers after 1pm. Mostly sunny, with a high near 93. Calm wind becoming south southwest 5 to 7 mph in the morning.
Saturday Night
A slight chance of showers. Partly cloudy, with a low around 69. Calm wind.
Sunday
A slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 92. Calm wind becoming southwest 5 to 8 mph in the morning.
Sunday Night
Mostly clear, with a low around 68. North wind around 5 mph becoming light and variable.
Monday
Sunny, with a high near 92. South wind 5 to 10 mph.
Monday Night
A chance of showers and thunderstorms. Mostly clear, with a low around 69. South wind around 7 mph.
Tuesday
A chance of showers and thunderstorms. Mostly sunny, with a high near 90. South southwest wind 6 to 9 mph becoming west in the afternoon.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Royalton IL
 37.87°N 89.11°W
Last Update:
5:41 pm CDT Sep 8, 2026
Forecast Valid:
6pm CDT Sep 8, 2026-6pm CDT Sep 15, 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