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

Marion - Williamson County Regional Airport (KMWA)

Lat: 37.77°NLon: 89.01°WElev: 486ft.

Fair

32°F

0°C

Humidity 51%
Wind Speed NW 14 mph
Barometer 30.50 in
Dewpoint 16°F (-9°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 11 Jan 9:47 am CST
Extended Forecast for

Simpson IL

  • Today

    Today: Sunny, with a high near 40. North northwest wind 5 to 10 mph becoming light northwest in the afternoon. Winds could gust as high as 20 mph.

    High: 40 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 25. Calm wind.

    Low: 25 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 50. Light south southwest wind becoming southwest 5 to 9 mph in the morning. Winds could gust as high as 18 mph.

    High: 50 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 33. South southwest wind 3 to 6 mph.

    Low: 33 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 57. Southwest wind 6 to 13 mph, with gusts as high as 23 mph.

    High: 57 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after midnight. Mostly cloudy, with a low around 41. West wind 3 to 7 mph.

    Low: 41 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Wednesday

    Wednesday: A 20 percent chance of showers. Partly sunny, with a high near 47. Light west wind becoming northwest 6 to 11 mph in the morning. Winds could gust as high as 22 mph.

    High: 47 °F

    Slight Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 19. North northwest wind 5 to 7 mph.

    Low: 19 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 37. North northwest wind around 6 mph becoming light and variable in the afternoon.

    High: 37 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 40. North northwest wind 5 to 10 mph becoming light northwest in the afternoon. Winds could gust as high as 20 mph.
Tonight
Clear, with a low around 25. Calm wind.
Monday
Sunny, with a high near 50. Light south southwest wind becoming southwest 5 to 9 mph in the morning. Winds could gust as high as 18 mph.
Monday Night
Mostly clear, with a low around 33. South southwest wind 3 to 6 mph.
Tuesday
Mostly sunny, with a high near 57. Southwest wind 6 to 13 mph, with gusts as high as 23 mph.
Tuesday Night
A 20 percent chance of showers after midnight. Mostly cloudy, with a low around 41. West wind 3 to 7 mph.
Wednesday
A 20 percent chance of showers. Partly sunny, with a high near 47. Light west wind becoming northwest 6 to 11 mph in the morning. Winds could gust as high as 22 mph.
Wednesday Night
Mostly cloudy, with a low around 19. North northwest wind 5 to 7 mph.
Thursday
Mostly sunny, with a high near 37. North northwest wind around 6 mph becoming light and variable in the afternoon.
Thursday Night
Partly cloudy, with a low around 25. Calm wind becoming southwest around 6 mph after midnight.
Friday
Partly sunny, with a high near 44. West wind 5 to 10 mph, with gusts as high as 18 mph.
Friday Night
Mostly cloudy, with a low around 24. Light west wind.
Saturday
Partly sunny, with a high near 37. West wind 5 to 9 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Simpson IL
 37.46°N 88.77°W
Last Update:
9:32 am CST Jan 11, 2026
Forecast Valid:
10am CST Jan 11, 2026-6pm CST Jan 17, 2026
 
Forecast Discussion
 
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Additional Resources

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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