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.

Thunderstorm Rain Fog/Mist

58°F

14°C

Humidity 97%
Wind Speed NW 7 mph
Barometer 29.65 in (1003.6 mb)
Dewpoint 57°F (14°C)
Visibility 1.75 mi
Last update 11 Mar 4:51 am CDT
Extended Forecast for

2 Miles S Illiopolis IL

  • Overnight

    Overnight: Showers and possibly a thunderstorm. Steady temperature around 61. West southwest wind around 16 mph, with gusts as high as 26 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 61 °F

    T-storms

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm before 1pm, then a chance of showers between 1pm and 4pm. Temperature falling to around 42 by 3pm. Breezy, with a west southwest wind 14 to 23 mph becoming northwest in the morning. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.

    High: 60 °F⇓

    Breezy.
    T-storms then
    Showers
    Likely

  • Wednesday Night

    Wednesday Night: Mostly cloudy, then gradually becoming clear, with a low around 29. Blustery, with a north northwest wind 16 to 21 mph decreasing to 7 to 12 mph after midnight. Winds could gust as high as 30 mph.

    Low: 29 °F

    Mostly Cloudy
    and Blustery
    then Clear

  • Thursday

    Thursday: Increasing clouds, with a high near 51. West southwest wind 6 to 15 mph, with gusts as high as 21 mph.

    High: 51 °F

    Increasing
    Clouds

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 41. Breezy, with a south wind 14 to 19 mph increasing to 20 to 25 mph after midnight. Winds could gust as high as 37 mph.

    Low: 41 °F

    Mostly Cloudy
    and Breezy

  • Friday

    Friday: Partly sunny, with a high near 55. Breezy, with a southwest wind 18 to 23 mph becoming west northwest in the afternoon. Winds could gust as high as 33 mph.

    High: 55 °F

    Partly Sunny
    and Breezy

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 33. Northwest wind 6 to 10 mph becoming east northeast after midnight. Winds could gust as high as 16 mph.

    Low: 33 °F

    Mostly Cloudy

  • Saturday

    Saturday: Mostly cloudy, with a high near 55.

    High: 55 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 46. Breezy.

    Low: 46 °F

    Mostly Cloudy
    then Chance
    Showers and
    Breezy

Detailed Forecast

Overnight
Showers and possibly a thunderstorm. Steady temperature around 61. West southwest wind around 16 mph, with gusts as high as 26 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday
Showers and possibly a thunderstorm before 1pm, then a chance of showers between 1pm and 4pm. Temperature falling to around 42 by 3pm. Breezy, with a west southwest wind 14 to 23 mph becoming northwest in the morning. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.
Wednesday Night
Mostly cloudy, then gradually becoming clear, with a low around 29. Blustery, with a north northwest wind 16 to 21 mph decreasing to 7 to 12 mph after midnight. Winds could gust as high as 30 mph.
Thursday
Increasing clouds, with a high near 51. West southwest wind 6 to 15 mph, with gusts as high as 21 mph.
Thursday Night
Mostly cloudy, with a low around 41. Breezy, with a south wind 14 to 19 mph increasing to 20 to 25 mph after midnight. Winds could gust as high as 37 mph.
Friday
Partly sunny, with a high near 55. Breezy, with a southwest wind 18 to 23 mph becoming west northwest in the afternoon. Winds could gust as high as 33 mph.
Friday Night
Mostly cloudy, with a low around 33. Northwest wind 6 to 10 mph becoming east northeast after midnight. Winds could gust as high as 16 mph.
Saturday
Mostly cloudy, with a high near 55.
Saturday Night
A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 46. Breezy.
Sunday
Showers. High near 60. Breezy. Chance of precipitation is 90%.
Sunday Night
A chance of rain and snow showers. Mostly cloudy, with a low around 21. Blustery.
Monday
Mostly sunny, with a high near 32. Breezy.
Monday Night
Partly cloudy, with a low around 16.
Tuesday
Partly sunny, with a high near 37.
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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:
5:26 am CDT Mar 11, 2026
Forecast Valid:
5am CDT Mar 11, 2026-6pm CDT Mar 17, 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