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

59°F

15°C

Humidity 78%
Wind Speed SE 7 mph
Barometer 30.02 in (1016.3 mb)
Dewpoint 52°F (11°C)
Visibility 10.00 mi
Last update 17 Oct 1:54 am CDT
Extended Forecast for

2 Miles S Illiopolis IL

  • Overnight

    Overnight: Partly cloudy, with a low around 57. South southeast wind around 10 mph, with gusts as high as 16 mph.

    Low: 57 °F

    Partly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 80. South wind 9 to 15 mph, with gusts as high as 21 mph.

    High: 80 °F

    Partly Sunny

  • Friday Night

    Friday Night: A 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. South wind 11 to 13 mph, with gusts as high as 20 mph.

    Low: 61 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Saturday

    Saturday: A chance of thunderstorms, then showers and possibly a thunderstorm after 7am. High near 76. South southwest wind 10 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.

    High: 76 °F

    Showers

  • Saturday Night

    Saturday Night: Showers and possibly a thunderstorm before 1am, then showers likely. Low around 47. South southwest wind 10 to 18 mph becoming west northwest after midnight. Winds could gust as high as 26 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 47 °F

    Showers

  • Sunday

    Sunday: Partly sunny, then gradually becoming sunny, with a high near 61. Breezy, with a west northwest wind 20 to 22 mph, with gusts as high as 30 mph.

    High: 61 °F

    Becoming
    Sunny and
    Breezy

  • Sunday Night

    Sunday Night: Clear, with a low around 41. West northwest wind 6 to 10 mph becoming southwest after midnight. Winds could gust as high as 15 mph.

    Low: 41 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 69. Breezy.

    High: 69 °F

    Sunny then
    Sunny and
    Breezy

  • Monday Night

    Monday Night: Mostly clear, with a low around 46.

    Low: 46 °F

    Mostly Clear

Detailed Forecast

Overnight
Partly cloudy, with a low around 57. South southeast wind around 10 mph, with gusts as high as 16 mph.
Friday
Partly sunny, with a high near 80. South wind 9 to 15 mph, with gusts as high as 21 mph.
Friday Night
A 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. South wind 11 to 13 mph, with gusts as high as 20 mph.
Saturday
A chance of thunderstorms, then showers and possibly a thunderstorm after 7am. High near 76. South southwest wind 10 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Saturday Night
Showers and possibly a thunderstorm before 1am, then showers likely. Low around 47. South southwest wind 10 to 18 mph becoming west northwest after midnight. Winds could gust as high as 26 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Sunday
Partly sunny, then gradually becoming sunny, with a high near 61. Breezy, with a west northwest wind 20 to 22 mph, with gusts as high as 30 mph.
Sunday Night
Clear, with a low around 41. West northwest wind 6 to 10 mph becoming southwest after midnight. Winds could gust as high as 15 mph.
Monday
Sunny, with a high near 69. Breezy.
Monday Night
Mostly clear, with a low around 46.
Tuesday
Sunny, with a high near 62. Breezy.
Tuesday Night
Mostly clear, with a low around 38.
Wednesday
Sunny, with a high near 64.
Wednesday Night
A chance of showers. Partly cloudy, with a low around 44.
Thursday
Mostly sunny, with a high near 64.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
2 Miles S Illiopolis IL
 39.83°N 89.26°W (Elev. 600 ft)
Last Update:
2:05 am CDT Oct 17, 2025
Forecast Valid:
2am CDT Oct 17, 2025-6pm CDT Oct 23, 2025
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation