National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Fair

80°F

27°C

Humidity 79%
Wind Speed SW 9 mph
Barometer 30.07 in (1017.6 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 14 Aug 1:54 pm CDT
Extended Forecast for

Assumption IL

Heat Advisory August 14, 02:08pm until August 16, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 14, 02:08pm until August 16, 08:00pm

    NOW until 8:00pm Sun

    Heat Advisory

  • This Afternoon

    High: 87 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A slight chance of showers and thunderstorms before 4am, then a slight chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 73. East wind 5 to 7 mph, with gusts as high as 17 mph. Chance of precipitation is 20%.

    Low: 73 °F

    Partly Cloudy
    then Slight
    Chance
    T-storms

  • Saturday

    Saturday: A 30 percent chance of showers and thunderstorms, mainly before 11am. Partly sunny, with a high near 94. Heat index values as high as 109. South wind 6 to 8 mph.

    High: 94 °F

    Chance
    T-storms then
    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 74. South southwest wind around 6 mph.

    Low: 74 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 91. West northwest wind 6 to 8 mph.

    High: 91 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 68. North northwest wind 3 to 6 mph.

    Low: 68 °F

    Partly Cloudy
    then Chance
    Showers

  • Monday

    Monday: Mostly sunny, with a high near 85. North northwest wind 5 to 7 mph.

    High: 85 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 63.

    Low: 63 °F

    Partly Cloudy

Detailed Forecast

This Afternoon
A 20 percent chance of showers and thunderstorms before 3pm. Partly sunny, with a high near 87. South wind around 7 mph.
Tonight
A slight chance of showers and thunderstorms before 4am, then a slight chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 73. East wind 5 to 7 mph, with gusts as high as 17 mph. Chance of precipitation is 20%.
Saturday
A 30 percent chance of showers and thunderstorms, mainly before 11am. Partly sunny, with a high near 94. Heat index values as high as 109. South wind 6 to 8 mph.
Saturday Night
Partly cloudy, with a low around 74. South southwest wind around 6 mph.
Sunday
Partly sunny, with a high near 91. West northwest wind 6 to 8 mph.
Sunday Night
A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 68. North northwest wind 3 to 6 mph.
Monday
Mostly sunny, with a high near 85. North northwest wind 5 to 7 mph.
Monday Night
Partly cloudy, with a low around 63.
Tuesday
Sunny, with a high near 86.
Tuesday Night
Partly cloudy, with a low around 68.
Wednesday
Partly sunny, with a high near 89.
Wednesday Night
A chance of showers. Mostly cloudy, with a low around 66.
Thursday
Mostly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Assumption IL
 39.51°N 89.05°W (Elev. 636 ft)
Last Update:
1:41 pm CDT Aug 14, 2026
Forecast Valid:
2pm CDT Aug 14, 2026-6pm CDT Aug 20, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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