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Current conditions at

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Fair

65°F

18°C

Humidity 73%
Wind Speed Calm
Barometer 29.97 in (1014.6 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 11 Oct 7:54 pm CDT
Extended Forecast for

Assumption IL

  • Tonight

    Tonight: Mostly clear, with a low around 61. Calm wind becoming south around 6 mph after midnight.

    Low: 61 °F

    Mostly Clear

  • Columbus Day

    Columbus Day: Sunny, with a high near 91. Southwest wind 6 to 13 mph, with gusts as high as 18 mph.

    High: 91 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 69. South southwest wind 7 to 9 mph, with gusts as high as 17 mph.

    Low: 69 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 92. West southwest wind 9 to 11 mph, with gusts as high as 17 mph.

    High: 92 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms after 1am. Increasing clouds, with a low around 68. Southwest wind 3 to 5 mph.

    Low: 68 °F

    Mostly Clear
    then Chance
    T-storms

  • Wednesday

    Wednesday: Showers likely, then showers and possibly a thunderstorm after 1pm. High near 81. Light and variable wind becoming west southwest around 5 mph in the morning. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 81 °F

    Showers

  • Wednesday Night

    Wednesday Night: Showers likely, mainly after 1am. Mostly cloudy, with a low around 60. Northeast wind 5 to 9 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 60 °F

    Showers
    Likely

  • Thursday

    Thursday: Showers, with thunderstorms also possible after 1pm. High near 75. Chance of precipitation is 80%.

    High: 75 °F

    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 52. Chance of precipitation is 50%.

    Low: 52 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Mostly clear, with a low around 61. Calm wind becoming south around 6 mph after midnight.
Columbus Day
Sunny, with a high near 91. Southwest wind 6 to 13 mph, with gusts as high as 18 mph.
Monday Night
Mostly clear, with a low around 69. South southwest wind 7 to 9 mph, with gusts as high as 17 mph.
Tuesday
Sunny, with a high near 92. West southwest wind 9 to 11 mph, with gusts as high as 17 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms after 1am. Increasing clouds, with a low around 68. Southwest wind 3 to 5 mph.
Wednesday
Showers likely, then showers and possibly a thunderstorm after 1pm. High near 81. Light and variable wind becoming west southwest around 5 mph in the morning. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Wednesday Night
Showers likely, mainly after 1am. Mostly cloudy, with a low around 60. Northeast wind 5 to 9 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
Thursday
Showers, with thunderstorms also possible after 1pm. High near 75. Chance of precipitation is 80%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 52. Chance of precipitation is 50%.
Friday
Partly sunny, with a high near 64. Breezy.
Friday Night
Partly cloudy, with a low around 37.
Saturday
Sunny, with a high near 59.
Saturday Night
Clear, with a low around 35.
Sunday
Sunny, with a high near 66.
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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:
7:36 pm CDT Oct 11, 2026
Forecast Valid:
8pm CDT Oct 11, 2026-6pm CDT Oct 18, 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