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

72°F

22°C

Humidity 64%
Wind Speed Calm
Barometer 29.99 in (1015.0 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Last update 19 Jun 8:54 pm CDT
Extended Forecast for

4 Miles WSW Sullivan IL

  • Tonight

    Tonight: A 20 percent chance of showers after 3am. Mostly cloudy, with a low around 61. Calm wind becoming west around 5 mph after midnight.

    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 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. Northwest wind around 5 mph becoming calm.

    Low: 61 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Sunday

    Sunday: A chance of showers before 7am, then showers likely and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 78. East southeast wind 6 to 13 mph, with gusts as high as 23 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

    High: 78 °F

    Showers
    Likely then
    T-storms

  • Sunday Night

    Sunday Night: Showers and thunderstorms, mainly before 1am. Low around 62. South southwest wind 9 to 13 mph becoming north northwest after midnight. Winds could gust as high as 21 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.

    Low: 62 °F

    T-storms

  • Monday

    Monday: Partly sunny, with a high near 74. North wind around 10 mph, with gusts as high as 20 mph.

    High: 74 °F

    Partly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 54. North northeast wind 5 to 9 mph, with gusts as high as 15 mph.

    Low: 54 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 76.

    High: 76 °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 3am. Mostly cloudy, with a low around 61. Calm wind becoming west around 5 mph after midnight.
Saturday
Mostly sunny, with a high near 81. Northwest wind 3 to 7 mph.
Saturday Night
A 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. Northwest wind around 5 mph becoming calm.
Sunday
A chance of showers before 7am, then showers likely and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 78. East southeast wind 6 to 13 mph, with gusts as high as 23 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 62. South southwest wind 9 to 13 mph becoming north northwest after midnight. Winds could gust as high as 21 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Monday
Partly sunny, with a high near 74. North wind around 10 mph, with gusts as high as 20 mph.
Monday Night
Partly cloudy, with a low around 54. North northeast wind 5 to 9 mph, with gusts as high as 15 mph.
Tuesday
Mostly sunny, with a high near 76.
Tuesday Night
Partly cloudy, with a low around 58.
Wednesday
Sunny, with a high near 77.
Wednesday Night
Mostly clear, with a low around 58.
Thursday
Mostly sunny, with a high near 77.
Thursday Night
Partly cloudy, with a low around 58.
Friday
Mostly sunny, with a high near 78.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles WSW Sullivan IL
 39.57°N 88.67°W (Elev. 676 ft)
Last Update:
7:51 pm CDT Jun 19, 2026
Forecast Valid:
9pm CDT Jun 19, 2026-6pm CDT Jun 26, 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