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.

N/A

Humidity NA
Wind Speed NA
Barometer NA
Dewpoint N/A
Visibility NA
Last update *** Not a current observation ***
Extended Forecast for

Simpson IL

Flood Advisory until March 5, 02:45am
Click here for hazard details and duration
Flood Advisory
  •  
    Flood Advisory until March 5, 02:45am

    NOW until 2:45am Thu

    Flood Advisory

  • Overnight

    Low: 60 °F

    Heavy Rain
    and Patchy
    Fog

  • Thursday

    Thursday: Showers and possibly a thunderstorm, mainly before 3pm, then a chance of showers and thunderstorms after 3pm. Patchy fog before noon. High near 71. Southwest wind 7 to 11 mph, with gusts as high as 18 mph. Chance of precipitation is 90%.

    High: 71 °F

    Showers and
    Patchy Fog

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before midnight, then a slight chance of showers between midnight and 2am. Patchy fog between 1am and 4am. Otherwise, mostly cloudy, with a low around 59. South southwest wind around 6 mph becoming calm. Chance of precipitation is 30%.

    Low: 59 °F

    Chance
    T-storms then
    Slight Chance
    Showers and
    Patchy Fog

  • Friday

    Friday: A 20 percent chance of showers after noon. Partly sunny, with a high near 78. South southwest wind 6 to 14 mph, with gusts as high as 24 mph.

    High: 78 °F

    Partly Sunny
    then Slight
    Chance
    Showers

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm after midnight. Mostly cloudy, with a low around 62. South wind 6 to 10 mph, with gusts as high as 23 mph. Chance of precipitation is 60%.

    Low: 62 °F

    Mostly Cloudy
    then Showers
    Likely

  • Saturday

    Saturday: Showers and possibly a thunderstorm. High near 72. South southwest wind 6 to 10 mph becoming west northwest in the afternoon. Winds could gust as high as 22 mph. Chance of precipitation is 90%.

    High: 72 °F

    Showers then
    Chance
    Showers

  • Saturday Night

    Saturday Night: A 20 percent chance of showers before midnight. Mostly cloudy, with a low around 44. Northwest wind around 5 mph becoming calm in the evening.

    Low: 44 °F

    Slight Chance
    Showers then
    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 63. Light and variable wind.

    High: 63 °F

    Mostly Sunny

Detailed Forecast

Overnight
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 3am. Some of the storms could produce heavy rainfall. Patchy fog after 5am. Low around 60. South wind around 7 mph. Chance of precipitation is 90%.
Thursday
Showers and possibly a thunderstorm, mainly before 3pm, then a chance of showers and thunderstorms after 3pm. Patchy fog before noon. High near 71. Southwest wind 7 to 11 mph, with gusts as high as 18 mph. Chance of precipitation is 90%.
Thursday Night
A chance of showers and thunderstorms before midnight, then a slight chance of showers between midnight and 2am. Patchy fog between 1am and 4am. Otherwise, mostly cloudy, with a low around 59. South southwest wind around 6 mph becoming calm. Chance of precipitation is 30%.
Friday
A 20 percent chance of showers after noon. Partly sunny, with a high near 78. South southwest wind 6 to 14 mph, with gusts as high as 24 mph.
Friday Night
Showers likely and possibly a thunderstorm after midnight. Mostly cloudy, with a low around 62. South wind 6 to 10 mph, with gusts as high as 23 mph. Chance of precipitation is 60%.
Saturday
Showers and possibly a thunderstorm. High near 72. South southwest wind 6 to 10 mph becoming west northwest in the afternoon. Winds could gust as high as 22 mph. Chance of precipitation is 90%.
Saturday Night
A 20 percent chance of showers before midnight. Mostly cloudy, with a low around 44. Northwest wind around 5 mph becoming calm in the evening.
Sunday
Mostly sunny, with a high near 63. Light and variable wind.
Sunday Night
Mostly clear, with a low around 45. Calm wind.
Monday
Mostly sunny, with a high near 73. Calm wind becoming south southwest 5 to 9 mph in the morning. Winds could gust as high as 20 mph.
Monday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 60. South southwest wind around 6 mph.
Tuesday
Showers likely. Cloudy, with a high near 76. South southwest wind 7 to 13 mph, with gusts as high as 25 mph.
Tuesday Night
Showers and possibly a thunderstorm. Cloudy, with a low around 57. South southwest wind 9 to 13 mph, with gusts as high as 28 mph.
Wednesday
Showers. Cloudy, with a high near 66. Southwest wind 11 to 14 mph becoming north northwest in the afternoon. Winds could gust as high as 26 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Simpson IL
 37.46°N 88.77°W
Last Update:
1:01 am CST Mar 5, 2026
Forecast Valid:
1am CST Mar 5, 2026-6pm CDT Mar 11, 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