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Hazardous Weather Conditions

Current conditions at

Marion - Williamson County Regional Airport (KMWA)

Lat: 37.77°NLon: 89.01°WElev: 486ft.

Partly Cloudy

90°F

32°C

Humidity 55%
Wind Speed S 5 mph
Barometer 30.11 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index97°F (36°C)
Last update 8 Sep 12:45 pm CDT
Extended Forecast for

Simpson IL

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

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 95. South wind around 6 mph.

    High: 95 °F

    Mostly Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 73. Calm wind becoming south southeast around 5 mph after midnight.

    Low: 73 °F

    Mostly Clear

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 3pm. Sunny and hot, with a high near 98. Heat index values as high as 106. South southwest wind 6 to 10 mph, with gusts as high as 18 mph.

    High: 98 °F

    Sunny then
    Slight Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely, mainly before 3am, then showers likely and possibly a thunderstorm after 5am. Mostly cloudy, with a low around 72. Light and variable wind. Chance of precipitation is 60%.

    Low: 72 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm before 10am, then showers between 10am and 1pm, then showers likely and possibly a thunderstorm after 1pm. High near 88. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 90%.

    High: 88 °F

    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 7pm, then a chance of showers between 7pm and 1am. Mostly cloudy, with a low around 66. Calm wind. Chance of precipitation is 30%.

    Low: 66 °F

    Chance
    Showers

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 88. Light and variable wind.

    High: 88 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: Partly cloudy, with a low around 67. Calm wind.

    Low: 67 °F

    Partly Cloudy

  • Saturday

    Saturday: A slight chance of showers after 1pm. Sunny, with a high near 93. Calm wind becoming south southwest around 6 mph in the afternoon.

    High: 93 °F

    Sunny then
    Slight Chance
    Showers

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 95. South wind around 6 mph.
Tonight
Mostly clear, with a low around 73. Calm wind becoming south southeast around 5 mph after midnight.
Wednesday
A 20 percent chance of showers and thunderstorms after 3pm. Sunny and hot, with a high near 98. Heat index values as high as 106. South southwest wind 6 to 10 mph, with gusts as high as 18 mph.
Wednesday Night
Showers and thunderstorms likely, mainly before 3am, then showers likely and possibly a thunderstorm after 5am. Mostly cloudy, with a low around 72. Light and variable wind. Chance of precipitation is 60%.
Thursday
Showers and possibly a thunderstorm before 10am, then showers between 10am and 1pm, then showers likely and possibly a thunderstorm after 1pm. High near 88. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 90%.
Thursday Night
A chance of showers and thunderstorms before 7pm, then a chance of showers between 7pm and 1am. Mostly cloudy, with a low around 66. Calm wind. Chance of precipitation is 30%.
Friday
A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 88. Light and variable wind.
Friday Night
Partly cloudy, with a low around 67. Calm wind.
Saturday
A slight chance of showers after 1pm. Sunny, with a high near 93. Calm wind becoming south southwest around 6 mph in the afternoon.
Saturday Night
Partly cloudy, with a low around 69. Calm wind.
Sunday
A slight chance of showers and thunderstorms. Sunny, with a high near 93. Calm wind becoming south southwest around 6 mph in the morning.
Sunday Night
Mostly clear, with a low around 68. Calm wind.
Monday
Sunny, with a high near 92. Calm wind becoming south 5 to 7 mph in the morning.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Simpson IL
 37.46°N 88.77°W
Last Update:
1:16 pm CDT Sep 8, 2026
Forecast Valid:
1pm CDT Sep 8, 2026-6pm CDT Sep 14, 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