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

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Fair

41°F

5°C

Humidity 62%
Wind Speed SW 7 mph
Barometer 30.15 in (1021.4 mb)
Dewpoint 29°F (-2°C)
Visibility 10.00 mi
Wind Chill36°F (2°C)
Last update 12 Jan 4:54 pm CST
Extended Forecast for

2 Miles S Illiopolis IL

  • Tonight

    Tonight: Increasing clouds, with a low around 33. South southwest wind 6 to 10 mph, with gusts as high as 21 mph.

    Low: 33 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Partly sunny, with a high near 54. West wind 11 to 17 mph, with gusts as high as 26 mph.

    High: 54 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 34. West wind 9 to 15 mph, with gusts as high as 24 mph.

    Low: 34 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly cloudy, with a temperature falling to around 27 by 5pm. Breezy, with a north northwest wind 17 to 25 mph, with gusts as high as 37 mph.

    High: 35 °F⇓

    Mostly Cloudy
    and Breezy

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 14. North northwest wind 13 to 18 mph, with gusts as high as 30 mph.

    Low: 14 °F

    Partly Cloudy

  • Thursday

    Thursday: Increasing clouds, with a high near 28. Northwest wind 8 to 11 mph becoming southwest in the afternoon. Winds could gust as high as 17 mph.

    High: 28 °F

    Increasing
    Clouds

  • Thursday Night

    Thursday Night: A 50 percent chance of snow. Mostly cloudy, with a low around 22. South southwest wind 7 to 14 mph, with gusts as high as 22 mph.

    Low: 22 °F

    Chance Snow

  • Friday

    Friday: A 40 percent chance of snow after noon. Mostly cloudy, with a high near 37.

    High: 37 °F

    Mostly Cloudy
    then Chance
    Snow

  • Friday Night

    Friday Night: A 30 percent chance of snow before midnight. Mostly cloudy, with a low around 15.

    Low: 15 °F

    Chance Snow
    then Mostly
    Cloudy

Detailed Forecast

Tonight
Increasing clouds, with a low around 33. South southwest wind 6 to 10 mph, with gusts as high as 21 mph.
Tuesday
Partly sunny, with a high near 54. West wind 11 to 17 mph, with gusts as high as 26 mph.
Tuesday Night
Mostly cloudy, with a low around 34. West wind 9 to 15 mph, with gusts as high as 24 mph.
Wednesday
Mostly cloudy, with a temperature falling to around 27 by 5pm. Breezy, with a north northwest wind 17 to 25 mph, with gusts as high as 37 mph.
Wednesday Night
Partly cloudy, with a low around 14. North northwest wind 13 to 18 mph, with gusts as high as 30 mph.
Thursday
Increasing clouds, with a high near 28. Northwest wind 8 to 11 mph becoming southwest in the afternoon. Winds could gust as high as 17 mph.
Thursday Night
A 50 percent chance of snow. Mostly cloudy, with a low around 22. South southwest wind 7 to 14 mph, with gusts as high as 22 mph.
Friday
A 40 percent chance of snow after noon. Mostly cloudy, with a high near 37.
Friday Night
A 30 percent chance of snow before midnight. Mostly cloudy, with a low around 15.
Saturday
Mostly cloudy, with a high near 23.
Saturday Night
Mostly cloudy, with a low around 5.
Sunday
Mostly sunny, with a high near 19.
Sunday Night
Partly cloudy, with a low around 9.
M.L.King Day
Mostly sunny, with a high near 29.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
2 Miles S Illiopolis IL
 39.83°N 89.26°W (Elev. 600 ft)
Last Update:
3:36 pm CST Jan 12, 2026
Forecast Valid:
5pm CST Jan 12, 2026-6pm CST Jan 19, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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