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

52°F

11°C

Humidity 75%
Wind Speed W 7 mph
Barometer 30.07 in (1018.4 mb)
Dewpoint 44°F (7°C)
Visibility 10.00 mi
Wind Chill50°F (10°C)
Last update 10 Nov 7:54 am CST
Extended Forecast for

Illiopolis IL

  • Today

    Today: Sunny, with a high near 68. West northwest wind around 6 mph becoming light and variable in the afternoon.

    High: 68 °F

    Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 43. Light and variable wind.

    Low: 43 °F

    Increasing
    Clouds

  • Veterans Day

    Veterans Day: A slight chance of showers and thunderstorms between 1pm and 3pm. Mostly sunny, with a high near 65. South wind 5 to 15 mph becoming northwest in the afternoon. Winds could gust as high as 24 mph. Chance of precipitation is 20%.

    High: 65 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 38. North northwest wind 11 to 15 mph, with gusts as high as 23 mph.

    Low: 38 °F

    Partly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 48. North northwest wind 11 to 17 mph, with gusts as high as 23 mph.

    High: 48 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 29. North northwest wind 8 to 14 mph, with gusts as high as 18 mph.

    Low: 29 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 43. North northwest wind 9 to 14 mph, with gusts as high as 18 mph.

    High: 43 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 23.

    Low: 23 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 46.

    High: 46 °F

    Sunny

Detailed Forecast

Today
Sunny, with a high near 68. West northwest wind around 6 mph becoming light and variable in the afternoon.
Tonight
Increasing clouds, with a low around 43. Light and variable wind.
Veterans Day
A slight chance of showers and thunderstorms between 1pm and 3pm. Mostly sunny, with a high near 65. South wind 5 to 15 mph becoming northwest in the afternoon. Winds could gust as high as 24 mph. Chance of precipitation is 20%.
Wednesday Night
Partly cloudy, with a low around 38. North northwest wind 11 to 15 mph, with gusts as high as 23 mph.
Thursday
Partly sunny, with a high near 48. North northwest wind 11 to 17 mph, with gusts as high as 23 mph.
Thursday Night
Partly cloudy, with a low around 29. North northwest wind 8 to 14 mph, with gusts as high as 18 mph.
Friday
Sunny, with a high near 43. North northwest wind 9 to 14 mph, with gusts as high as 18 mph.
Friday Night
Mostly clear, with a low around 23.
Saturday
Sunny, with a high near 46.
Saturday Night
Mostly clear, with a low around 28.
Sunday
Mostly sunny, with a high near 51.
Sunday Night
Partly cloudy, with a low around 33.
Monday
Mostly sunny, with a high near 54.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Illiopolis IL
 39.85°N 89.23°W (Elev. 600 ft)
Last Update:
5:16 am CST Nov 10, 2026
Forecast Valid:
7am CST Nov 10, 2026-6pm CST Nov 16, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation