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

75°F

24°C

Humidity 54%
Wind Speed W 6 mph
Barometer 30.01 in (1015.9 mb)
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Last update 19 Jun 7:54 pm CDT
Extended Forecast for

2 Miles S Illiopolis IL

  • Tonight

    Tonight: A 20 percent chance of showers after 2am. Mostly cloudy, with a low around 61. South southwest wind 3 to 5 mph.

    Low: 61 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Saturday

    Saturday: Mostly sunny, with a high near 81. Northwest wind 3 to 7 mph.

    High: 81 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A slight chance of showers between 3am and 4am, then a chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 62. Calm wind becoming east around 6 mph after midnight. Chance of precipitation is 30%.

    Low: 62 °F

    Partly Cloudy
    then Chance
    Showers

  • Sunday

    Sunday: A chance of showers before 7am, then showers and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 77. East southeast wind 9 to 17 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

    High: 77 °F

    Showers then
    T-storms

  • Sunday Night

    Sunday Night: Showers and thunderstorms, mainly before 1am. Low around 61. South southwest wind 13 to 16 mph becoming north after midnight. Winds could gust as high as 23 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 61 °F

    T-storms

  • Monday

    Monday: Partly sunny, with a high near 75. North wind around 14 mph, with gusts as high as 20 mph.

    High: 75 °F

    Partly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 55. Northeast wind 5 to 11 mph, with gusts as high as 16 mph.

    Low: 55 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 77.

    High: 77 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 58.

    Low: 58 °F

    Partly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of showers after 2am. Mostly cloudy, with a low around 61. South southwest wind 3 to 5 mph.
Saturday
Mostly sunny, with a high near 81. Northwest wind 3 to 7 mph.
Saturday Night
A slight chance of showers between 3am and 4am, then a chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 62. Calm wind becoming east around 6 mph after midnight. Chance of precipitation is 30%.
Sunday
A chance of showers before 7am, then showers and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 77. East southeast wind 9 to 17 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Sunday Night
Showers and thunderstorms, mainly before 1am. Low around 61. South southwest wind 13 to 16 mph becoming north after midnight. Winds could gust as high as 23 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Monday
Partly sunny, with a high near 75. North wind around 14 mph, with gusts as high as 20 mph.
Monday Night
Partly cloudy, with a low around 55. Northeast wind 5 to 11 mph, with gusts as high as 16 mph.
Tuesday
Mostly sunny, with a high near 77.
Tuesday Night
Partly cloudy, with a low around 58.
Wednesday
Mostly sunny, with a high near 78.
Wednesday Night
Mostly clear, with a low around 58.
Thursday
Mostly sunny, with a high near 78.
Thursday Night
A chance of showers. Partly cloudy, with a low around 59.
Friday
Mostly sunny, with a high near 79.
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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:
7:51 pm CDT Jun 19, 2026
Forecast Valid:
8pm CDT Jun 19, 2026-6pm CDT Jun 26, 2026
 
Forecast Discussion
 
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Additional Resources

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation