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Current conditions at

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Fair

48°F

9°C

Humidity 93%
Wind Speed Calm
Barometer 30.05 in (1017.5 mb)
Dewpoint 46°F (8°C)
Visibility 10.00 mi
Last update 8 Oct 5:54 am CDT
Extended Forecast for

Illiopolis IL

  • Today

    Today: Sunny, with a high near 82. Calm wind becoming west around 6 mph in the afternoon.

    High: 82 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 54. Calm wind becoming east around 5 mph after midnight.

    Low: 54 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 86. South wind 7 to 13 mph, with gusts as high as 18 mph.

    High: 86 °F

    Sunny

  • Friday Night

    Friday Night: Clear, with a low around 60. South southeast wind around 9 mph, with gusts as high as 16 mph.

    Low: 60 °F

    Clear

  • Saturday

    Saturday: Increasing clouds, with a high near 85. South wind 8 to 11 mph, with gusts as high as 17 mph.

    High: 85 °F

    Increasing
    Clouds

  • Saturday Night

    Saturday Night: Showers likely after 1am. Mostly cloudy, with a low around 59. Southeast wind 7 to 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 59 °F

    Mostly Cloudy
    then Showers
    Likely

  • Sunday

    Sunday: Partly sunny, with a high near 76. East wind 6 to 9 mph becoming north northwest in the afternoon.

    High: 76 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 56.

    Low: 56 °F

    Mostly Clear

  • Columbus Day

    Columbus Day: Sunny, with a high near 86.

    High: 86 °F

    Sunny

Detailed Forecast

Today
Sunny, with a high near 82. Calm wind becoming west around 6 mph in the afternoon.
Tonight
Mostly clear, with a low around 54. Calm wind becoming east around 5 mph after midnight.
Friday
Sunny, with a high near 86. South wind 7 to 13 mph, with gusts as high as 18 mph.
Friday Night
Clear, with a low around 60. South southeast wind around 9 mph, with gusts as high as 16 mph.
Saturday
Increasing clouds, with a high near 85. South wind 8 to 11 mph, with gusts as high as 17 mph.
Saturday Night
Showers likely after 1am. Mostly cloudy, with a low around 59. Southeast wind 7 to 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Sunday
Partly sunny, with a high near 76. East wind 6 to 9 mph becoming north northwest in the afternoon.
Sunday Night
Mostly clear, with a low around 56.
Columbus Day
Sunny, with a high near 86.
Monday Night
Mostly clear, with a low around 59.
Tuesday
Mostly sunny, with a high near 76.
Tuesday Night
Mostly clear, with a low around 48.
Wednesday
Sunny, with a high near 72.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Illiopolis IL
 39.83°N 89.23°W (Elev. 568 ft)
Last Update:
6:11 am CDT Oct 8, 2026
Forecast Valid:
6am CDT Oct 8, 2026-6pm CDT Oct 14, 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