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

77°F

25°C

Humidity 60%
Wind Speed S 10 mph
Barometer 30.02 in (1015.8 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 30 Aug 9:54 pm CDT
Extended Forecast for

Decatur IL

  • Tonight

    Tonight: Partly cloudy, with a low around 69. South wind around 8 mph, with gusts as high as 16 mph.

    Low: 69 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 94. South southwest wind 9 to 11 mph, with gusts as high as 17 mph.

    High: 94 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 74. South wind around 9 mph, with gusts as high as 15 mph.

    Low: 74 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 96. Heat index values as high as 103. Southwest wind around 8 mph.

    High: 96 °F

    Hot

  • Tuesday Night

    Tuesday Night: Clear, with a low around 76. South wind 5 to 8 mph.

    Low: 76 °F

    Clear

  • Wednesday

    Wednesday: Sunny and hot, with a high near 97. Southwest wind 7 to 9 mph, with gusts as high as 15 mph.

    High: 97 °F

    Hot

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 76. South southwest wind 5 to 7 mph.

    Low: 76 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 95.

    High: 95 °F

    Hot

  • Thursday Night

    Thursday Night: A 30 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 73.

    Low: 73 °F

    Partly Cloudy
    then Chance
    T-storms

Detailed Forecast

Tonight
Partly cloudy, with a low around 69. South wind around 8 mph, with gusts as high as 16 mph.
Monday
Sunny, with a high near 94. South southwest wind 9 to 11 mph, with gusts as high as 17 mph.
Monday Night
Mostly clear, with a low around 74. South wind around 9 mph, with gusts as high as 15 mph.
Tuesday
Sunny and hot, with a high near 96. Heat index values as high as 103. Southwest wind around 8 mph.
Tuesday Night
Clear, with a low around 76. South wind 5 to 8 mph.
Wednesday
Sunny and hot, with a high near 97. Southwest wind 7 to 9 mph, with gusts as high as 15 mph.
Wednesday Night
Mostly clear, with a low around 76. South southwest wind 5 to 7 mph.
Thursday
Mostly sunny and hot, with a high near 95.
Thursday Night
A 30 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 73.
Friday
Sunny, with a high near 92.
Friday Night
Mostly clear, with a low around 70.
Saturday
Mostly sunny, with a high near 90.
Saturday Night
Mostly clear, with a low around 67.
Sunday
Sunny, with a high near 87.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Decatur IL
 39.84°N 88.91°W (Elev. 620 ft)
Last Update:
10:36 pm CDT Aug 30, 2026
Forecast Valid:
10pm CDT Aug 30, 2026-6pm CDT Sep 6, 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