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.

Overcast

61°F

16°C

Humidity 90%
Wind Speed SW 17 G 29 mph
Barometer 29.85 in (1010.5 mb)
Dewpoint 58°F (14°C)
Visibility 10.00 mi
Last update 7 Mar 10:54 am CST
Extended Forecast for

Harristown IL

  • Today

    Today: A 30 percent chance of rain, mainly before 11am. Cloudy, with a temperature falling to around 45 by 5pm. Breezy, with a west northwest wind 16 to 21 mph, with gusts as high as 31 mph.

    High: 63 °F⇓

    Chance Rain
    and Breezy

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming mostly clear, with a low around 35. West northwest wind 6 to 15 mph, with gusts as high as 21 mph.

    Low: 35 °F

    Decreasing
    Clouds

  • Sunday

    Sunday: Sunny, with a high near 62. Southwest wind 8 to 16 mph, with gusts as high as 22 mph.

    High: 62 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 45. South southwest wind 11 to 14 mph, with gusts as high as 22 mph.

    Low: 45 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 73. Breezy, with a south southwest wind 14 to 20 mph, with gusts as high as 26 mph.

    High: 73 °F

    Sunny then
    Sunny and
    Breezy

  • Monday Night

    Monday Night: Mostly clear, with a low around 55. South southwest wind 10 to 13 mph, with gusts as high as 20 mph.

    Low: 55 °F

    Mostly Clear

  • Tuesday

    Tuesday: Showers likely and possibly a thunderstorm after noon. Partly sunny, with a high near 76. Breezy, with a south wind 10 to 20 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

    High: 76 °F

    Mostly Sunny
    then Showers
    Likely and
    Breezy

  • Tuesday Night

    Tuesday Night: Showers, with thunderstorms also possible after midnight. Low around 48. Breezy. Chance of precipitation is 90%.

    Low: 48 °F

    Showers and
    Breezy

  • Wednesday

    Wednesday: Showers, mainly before noon. High near 60. Breezy. Chance of precipitation is 80%.

    High: 60 °F

    Breezy.
    Showers then
    Chance
    Showers

Detailed Forecast

Today
A 30 percent chance of rain, mainly before 11am. Cloudy, with a temperature falling to around 45 by 5pm. Breezy, with a west northwest wind 16 to 21 mph, with gusts as high as 31 mph.
Tonight
Mostly cloudy, then gradually becoming mostly clear, with a low around 35. West northwest wind 6 to 15 mph, with gusts as high as 21 mph.
Sunday
Sunny, with a high near 62. Southwest wind 8 to 16 mph, with gusts as high as 22 mph.
Sunday Night
Clear, with a low around 45. South southwest wind 11 to 14 mph, with gusts as high as 22 mph.
Monday
Sunny, with a high near 73. Breezy, with a south southwest wind 14 to 20 mph, with gusts as high as 26 mph.
Monday Night
Mostly clear, with a low around 55. South southwest wind 10 to 13 mph, with gusts as high as 20 mph.
Tuesday
Showers likely and possibly a thunderstorm after noon. Partly sunny, with a high near 76. Breezy, with a south wind 10 to 20 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Tuesday Night
Showers, with thunderstorms also possible after midnight. Low around 48. Breezy. Chance of precipitation is 90%.
Wednesday
Showers, mainly before noon. High near 60. Breezy. Chance of precipitation is 80%.
Wednesday Night
Mostly cloudy, with a low around 31.
Thursday
Mostly sunny, with a high near 48.
Thursday Night
Mostly cloudy, with a low around 38. Breezy.
Friday
Mostly cloudy, with a high near 60. Breezy.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Harristown IL
 39.84°N 89.06°W (Elev. 699 ft)
Last Update:
10:06 am CST Mar 7, 2026
Forecast Valid:
10am CST Mar 7, 2026-6pm CDT Mar 13, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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