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

56°F

13°C

Humidity 55%
Wind Speed SE 7 mph
Barometer 29.81 in
Dewpoint 40°F (4°C)
Visibility 10.00 mi
Last update 14 Mar 11:55 pm CDT
Extended Forecast for

Simpson IL

Wind Advisory March 15, 10:00am until March 16, 07:00am
Click here for hazard details and duration
Wind Advisory

  • Overnight

    Overnight: Increasing clouds, with a low around 55. South wind 6 to 10 mph, with gusts as high as 20 mph.

    Low: 55 °F

    Increasing
    Clouds

  • Sunday

    Sunday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5pm. Mostly cloudy, with a high near 72. Breezy, with a south wind 13 to 21 mph, with gusts as high as 38 mph. Chance of precipitation is 60%.

    High: 72 °F

    Breezy.
    Mostly Cloudy
    then Showers
    Likely

  • Sunday Night

    Sunday Night: Showers and possibly a thunderstorm before 10pm, then a slight chance of showers between 10pm and 11pm. Low around 26. West northwest wind 14 to 17 mph, with gusts as high as 36 mph. Chance of precipitation is 90%.

    Low: 26 °F

    Showers then
    Mostly Cloudy

  • Monday

    Monday: Mostly cloudy, with a high near 35. West northwest wind around 15 mph, with gusts as high as 30 mph.

    High: 35 °F

    Mostly Cloudy

  • Monday Night

    Monday Night: Mostly clear, with a low around 17. West northwest wind 5 to 10 mph, with gusts as high as 21 mph.

    Low: 17 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 40. West northwest wind 3 to 6 mph.

    High: 40 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 29. Calm wind becoming south 5 to 8 mph after midnight. Winds could gust as high as 18 mph.

    Low: 29 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly cloudy, with a high near 58. South wind 10 to 13 mph, with gusts as high as 23 mph.

    High: 58 °F

    Mostly Cloudy

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 42. South southwest wind around 6 mph becoming calm in the evening.

    Low: 42 °F

    Partly Cloudy

Detailed Forecast

Overnight
Increasing clouds, with a low around 55. South wind 6 to 10 mph, with gusts as high as 20 mph.
Sunday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5pm. Mostly cloudy, with a high near 72. Breezy, with a south wind 13 to 21 mph, with gusts as high as 38 mph. Chance of precipitation is 60%.
Sunday Night
Showers and possibly a thunderstorm before 10pm, then a slight chance of showers between 10pm and 11pm. Low around 26. West northwest wind 14 to 17 mph, with gusts as high as 36 mph. Chance of precipitation is 90%.
Monday
Mostly cloudy, with a high near 35. West northwest wind around 15 mph, with gusts as high as 30 mph.
Monday Night
Mostly clear, with a low around 17. West northwest wind 5 to 10 mph, with gusts as high as 21 mph.
Tuesday
Sunny, with a high near 40. West northwest wind 3 to 6 mph.
Tuesday Night
Mostly cloudy, with a low around 29. Calm wind becoming south 5 to 8 mph after midnight. Winds could gust as high as 18 mph.
Wednesday
Mostly cloudy, with a high near 58. South wind 10 to 13 mph, with gusts as high as 23 mph.
Wednesday Night
Partly cloudy, with a low around 42. South southwest wind around 6 mph becoming calm in the evening.
Thursday
Sunny, with a high near 70. Calm wind becoming southwest around 6 mph in the morning.
Thursday Night
Partly cloudy, with a low around 46. Calm wind.
Friday
Mostly sunny, with a high near 74. Calm wind becoming southwest around 6 mph in the afternoon.
Friday Night
Partly cloudy, with a low around 50. Light and variable wind becoming west northwest around 5 mph after midnight.
Saturday
Partly sunny, with a high near 69. North northwest wind 5 to 8 mph.
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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:
11:36 pm CDT Mar 14, 2026
Forecast Valid:
12am CDT Mar 15, 2026-6pm CDT Mar 21, 2026
 
Forecast Discussion
 
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Additional Resources

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High Temperature

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Chance of Precipitation