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

Hazardous Weather Conditions

Current conditions at

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Overcast

29°F

-2°C

Humidity 72%
Wind Speed E 12 mph
Barometer 30.34 in (1028.3 mb)
Dewpoint 21°F (-6°C)
Visibility 10.00 mi
Wind Chill19°F (-7°C)
Last update 28 Nov 11:54 pm CST
Extended Forecast for

Illiopolis IL

Winter Storm Warning until November 30, 06:00am
Click here for hazard details and duration
Winter Storm Warning
  •  
    Winter Storm Warning until November 30, 06:00am

    NOW until 6:00am Sun

    Winter Storm Warning

  • Overnight

    Low: 25 °F

    Snow

  • Saturday

    Saturday: Snow before 5pm, then snow, possibly mixed with rain. The snow could be heavy at times. High near 35. Breezy, with a south southeast wind 16 to 22 mph, with gusts as high as 32 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 8 inches possible.

    High: 35 °F

    Breezy. Heavy
    Snow then
    Rain/Snow

  • Saturday Night

    Saturday Night: Rain and snow, becoming all snow after 11pm. Low around 23. Breezy, with a south wind 17 to 22 mph becoming west after midnight. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New snow accumulation of less than a half inch possible.

    Low: 23 °F

    Breezy.
    Rain/Snow
    then Chance
    Snow

  • Sunday

    Sunday: A 30 percent chance of snow before noon. Mostly cloudy, with a high near 27. Breezy, with a west northwest wind 13 to 21 mph, with gusts as high as 30 mph.

    High: 27 °F

    Chance Snow
    and Breezy
    then Mostly
    Cloudy

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 12. Northwest wind 6 to 11 mph becoming light and variable after midnight. Winds could gust as high as 16 mph.

    Low: 12 °F

    Mostly Cloudy

  • Monday

    Monday: A 40 percent chance of snow after noon. Cloudy, with a high near 26. Light east northeast wind.

    High: 26 °F

    Cloudy then
    Chance Snow

  • Monday Night

    Monday Night: A 50 percent chance of snow before midnight. Mostly cloudy, with a low around 14. Calm wind becoming north northwest around 5 mph after midnight.

    Low: 14 °F

    Chance Snow
    then Mostly
    Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 24.

    High: 24 °F

    Partly Sunny

Detailed Forecast

Overnight
Snow, mainly after 4am. Low around 25. East southeast wind 6 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 100%. Total nighttime snow accumulation of 1 to 2 inches possible.
Saturday
Snow before 5pm, then snow, possibly mixed with rain. The snow could be heavy at times. High near 35. Breezy, with a south southeast wind 16 to 22 mph, with gusts as high as 32 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 8 inches possible.
Saturday Night
Rain and snow, becoming all snow after 11pm. Low around 23. Breezy, with a south wind 17 to 22 mph becoming west after midnight. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New snow accumulation of less than a half inch possible.
Sunday
A 30 percent chance of snow before noon. Mostly cloudy, with a high near 27. Breezy, with a west northwest wind 13 to 21 mph, with gusts as high as 30 mph.
Sunday Night
Mostly cloudy, with a low around 12. Northwest wind 6 to 11 mph becoming light and variable after midnight. Winds could gust as high as 16 mph.
Monday
A 40 percent chance of snow after noon. Cloudy, with a high near 26. Light east northeast wind.
Monday Night
A 50 percent chance of snow before midnight. Mostly cloudy, with a low around 14. Calm wind becoming north northwest around 5 mph after midnight.
Tuesday
Partly sunny, with a high near 24.
Tuesday Night
Mostly cloudy, with a low around 14.
Wednesday
Partly sunny, with a high near 33.
Wednesday Night
Mostly cloudy, with a low around 12.
Thursday
Partly sunny, with a high near 23.
Thursday Night
Mostly cloudy, with a low around 10.
Friday
Mostly cloudy, with a high near 31.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Illiopolis IL
 39.83°N 89.23°W (Elev. 568 ft)
Last Update:
8:37 pm CST Nov 28, 2025
Forecast Valid:
12am CST Nov 29, 2025-6pm CST Dec 5, 2025
 
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