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.

A Few Clouds

68°F

20°C

Humidity 51%
Wind Speed NE 15 mph
Barometer 30.14 in (1020.4 mb)
Dewpoint 49°F (9°C)
Visibility 10.00 mi
Last update 20 May 5:54 pm CDT
Extended Forecast for

Decatur IL

  • Tonight

    Tonight: Partly cloudy, with a low around 48. Northeast wind 9 to 11 mph, with gusts as high as 18 mph.

    Low: 48 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 69. East wind 10 to 13 mph, with gusts as high as 21 mph.

    High: 69 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 52. East wind around 11 mph, with gusts as high as 18 mph.

    Low: 52 °F

    Mostly Cloudy

  • Friday

    Friday: Showers likely, mainly after 1pm. Mostly cloudy, with a high near 68. East wind 10 to 13 mph, with gusts as high as 20 mph. Chance of precipitation is 70%. New precipitation amounts between a quarter and half of an inch possible.

    High: 68 °F

    Chance
    Showers then
    Showers
    Likely

  • Friday Night

    Friday Night: Showers likely before 1am. Mostly cloudy, with a low around 58. East northeast wind 6 to 10 mph becoming west southwest after midnight. Winds could gust as high as 15 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 58 °F

    Showers
    Likely

  • Saturday

    Saturday: Mostly cloudy, with a high near 77. Southwest wind 7 to 9 mph.

    High: 77 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 59. West southwest wind around 6 mph becoming calm in the evening.

    Low: 59 °F

    Mostly Cloudy
    then Chance
    Showers

  • Sunday

    Sunday: A 30 percent chance of showers. Mostly cloudy, with a high near 78.

    High: 78 °F

    Chance
    Showers

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 59.

    Low: 59 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 48. Northeast wind 9 to 11 mph, with gusts as high as 18 mph.
Thursday
Mostly sunny, with a high near 69. East wind 10 to 13 mph, with gusts as high as 21 mph.
Thursday Night
Mostly cloudy, with a low around 52. East wind around 11 mph, with gusts as high as 18 mph.
Friday
Showers likely, mainly after 1pm. Mostly cloudy, with a high near 68. East wind 10 to 13 mph, with gusts as high as 20 mph. Chance of precipitation is 70%. New precipitation amounts between a quarter and half of an inch possible.
Friday Night
Showers likely before 1am. Mostly cloudy, with a low around 58. East northeast wind 6 to 10 mph becoming west southwest after midnight. Winds could gust as high as 15 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday
Mostly cloudy, with a high near 77. Southwest wind 7 to 9 mph.
Saturday Night
A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 59. West southwest wind around 6 mph becoming calm in the evening.
Sunday
A 30 percent chance of showers. Mostly cloudy, with a high near 78.
Sunday Night
Mostly cloudy, with a low around 59.
Memorial Day
Mostly cloudy, with a high near 79.
Monday Night
A chance of showers. Mostly cloudy, with a low around 62.
Tuesday
A chance of showers. Partly sunny, with a high near 80.
Tuesday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 65.
Wednesday
A chance of showers and thunderstorms. Partly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Decatur IL
 39.86°N 88.94°W (Elev. 682 ft)
Last Update:
4:36 pm CDT May 20, 2026
Forecast Valid:
6pm CDT May 20, 2026-6pm CDT May 27, 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