News Headlines
Hazardous Weather Conditions
Current conditions at
Decatur Airport (KDEC)
Lat: 39.83°NLon: 88.87°WElev: 670ft.
Light Rain
69°F
21°C
| Humidity | 87% |
| Wind Speed | SE 7 mph |
| Barometer | 30.03 in (1016.6 mb) |
| Dewpoint | 65°F (18°C) |
| Visibility | 9.00 mi |
| Last update | 15 Oct 10:54 am CDT |
Extended Forecast for
Illiopolis IL
Today
High: 76 °F
Showers
Tonight
Low: 46 °F
Breezy.
Showers
Likely then
Chance
ShowersFriday
High: 55 °F
Breezy.
Partly Sunny
then Chance
ShowersFriday Night
Low: 36 °F
Mostly Cloudy
then Patchy
FrostSaturday
High: 59 °F
Areas Frost
then SunnySaturday Night
Low: 35 °F
Clear then
Areas FrostSunday
High: 68 °F
Areas Frost
then SunnySunday Night
Low: 38 °F
Mostly Clear
Monday
High: 73 °F
Mostly Sunny
Detailed Forecast
Today
Showers and possibly a thunderstorm. High near 76. South southeast wind 9 to 13 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tonight
Showers likely and possibly a thunderstorm before 10pm, then a chance of showers between 10pm and 1am. Mostly cloudy, with a low around 46. Breezy, with a southwest wind 14 to 20 mph becoming northwest after midnight. Winds could gust as high as 29 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday
A 30 percent chance of showers, mainly after 3pm. Partly sunny, with a high near 55. Breezy, with a northwest wind 21 to 23 mph, with gusts as high as 32 mph.
Friday Night
Patchy frost after 5am. Otherwise, mostly cloudy, then gradually becoming mostly clear, with a low around 36. North wind 9 to 18 mph, with gusts as high as 25 mph.
Saturday
Areas of frost before 8am. Otherwise, sunny, with a high near 59. North wind around 6 mph becoming calm in the morning.
Saturday Night
Areas of frost after 4am. Otherwise, clear, with a low around 35. Calm wind becoming south southeast around 5 mph after midnight.
Sunday
Areas of frost before 8am. Otherwise, sunny, with a high near 68. South wind 5 to 9 mph.
Sunday Night
Mostly clear, with a low around 38.
Monday
Mostly sunny, with a high near 73.
Monday Night
Partly cloudy, with a low around 41.
Tuesday
Mostly sunny, with a high near 74.
Tuesday Night
Mostly clear, with a low around 44.
Wednesday
Sunny, with a high near 77.
Additional Forecasts and Information
Basemap Options
Click map to change the forecast location
Loading map...
Forecast AreaABOUT THIS FORECAST
Point Forecast:
Illiopolis IL
39.85°N 89.26°W (Elev. 607 ft)
39.85°N 89.26°W (Elev. 607 ft)
10:36 am CDT Oct 15, 2026
11am CDT Oct 15, 2026-6pm CDT Oct 21, 2026
Additional Resources
Radar & Satellite Image
Hourly Weather Forecast
