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.

A Few Clouds

83°F

28°C

Humidity 65%
Wind Speed SW 17 mph
Barometer 29.93 in (1012.6 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index87°F (31°C)
Last update 6 Jun 10:54 am CDT
Extended Forecast for

Harristown IL

  • Today

    Today: A 20 percent chance of showers and thunderstorms after 4pm. Partly sunny, with a high near 87. Southwest wind 11 to 13 mph, with gusts as high as 20 mph.

    High: 87 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before midnight. Mostly cloudy, with a low around 69. Southwest wind 5 to 9 mph becoming light south southwest after midnight.

    Low: 69 °F

    Slight Chance
    T-storms then
    Mostly Cloudy

  • Sunday

    Sunday: A slight chance of showers and thunderstorms before 9am, then a chance of showers between 9am and 10am, then a chance of showers and thunderstorms after 10am. Partly sunny, with a high near 85. Calm wind becoming southeast 5 to 9 mph in the afternoon. Chance of precipitation is 50%.

    High: 85 °F

    Chance
    Showers then
    Chance
    T-storms

  • Sunday Night

    Sunday Night: A chance of showers and thunderstorms between 10pm and 1am, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 68. Southeast wind around 10 mph, with gusts as high as 17 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 68 °F

    Chance
    T-storms then
    Showers
    Likely

  • Monday

    Monday: Showers, with thunderstorms also possible after 1pm. High near 83. South southeast wind around 14 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 83 °F

    Showers

  • Monday Night

    Monday Night: Showers and possibly a thunderstorm. Low around 68. South wind 7 to 11 mph, with gusts as high as 16 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 68 °F

    Showers

  • Tuesday

    Tuesday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 88. South southwest wind around 9 mph.

    High: 88 °F

    Partly Sunny
    then Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms. Mostly clear, with a low around 71.

    Low: 71 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Sunny, with a high near 93.

    High: 93 °F

    Sunny

Detailed Forecast

Today
A 20 percent chance of showers and thunderstorms after 4pm. Partly sunny, with a high near 87. Southwest wind 11 to 13 mph, with gusts as high as 20 mph.
Tonight
A 20 percent chance of showers and thunderstorms before midnight. Mostly cloudy, with a low around 69. Southwest wind 5 to 9 mph becoming light south southwest after midnight.
Sunday
A slight chance of showers and thunderstorms before 9am, then a chance of showers between 9am and 10am, then a chance of showers and thunderstorms after 10am. Partly sunny, with a high near 85. Calm wind becoming southeast 5 to 9 mph in the afternoon. Chance of precipitation is 50%.
Sunday Night
A chance of showers and thunderstorms between 10pm and 1am, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 68. Southeast wind around 10 mph, with gusts as high as 17 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Monday
Showers, with thunderstorms also possible after 1pm. High near 83. South southeast wind around 14 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Monday Night
Showers and possibly a thunderstorm. Low around 68. South wind 7 to 11 mph, with gusts as high as 16 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Tuesday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 88. South southwest wind around 9 mph.
Tuesday Night
A 30 percent chance of showers and thunderstorms. Mostly clear, with a low around 71.
Wednesday
Sunny, with a high near 93.
Wednesday Night
Mostly clear, with a low around 73.
Thursday
Sunny, with a high near 93.
Thursday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 72.
Friday
Sunny, with a high near 92.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Harristown IL
 39.84°N 89.06°W (Elev. 699 ft)
Last Update:
11:31 am CDT Jun 6, 2026
Forecast Valid:
11am CDT Jun 6, 2026-6pm CDT Jun 12, 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