Illinois City, IL Weather & Growing Conditions
Today
53°F
Chance Rain Showers then Cloudy
A chance of rain showers between 7am and noon. Cloudy, with a high near 53. Southwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 30%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 53°F | Chance Rain Showers then Cloudy | 15 mph SW | 25% |
| Tonight | 46°F | Mostly Cloudy | 10 to 15 mph SW | 12% |
| Thursday | 55°F | Rain Showers Likely | 10 to 15 mph W | 62% |
| Thursday Night | 41°F | Slight Chance Rain Showers then Mostly Cloudy | 10 mph N | 17% |
| Friday | 50°F | Partly Sunny | 5 to 10 mph N | 6% |
| Friday Night | 33°F | Partly Cloudy | 0 to 5 mph N | 0% |
| Saturday | 52°F | Sunny | 0 to 5 mph NW | 0% |
| Saturday Night | 35°F | Mostly Clear | 0 to 5 mph W | 1% |
| Sunday | 57°F | Sunny | 5 mph W | 1% |
| Sunday Night | 36°F | Clear | 0 to 5 mph W | 1% |
| Monday | 63°F | Sunny | 0 to 10 mph SW | 0% |
| Monday Night | 41°F | Mostly Clear | 5 mph W | 0% |
| Tuesday | 64°F | Sunny | 5 mph NW | 0% |
| Tuesday Night | 41°F | Mostly Clear | 0 mph | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Illinois City, IL
Last spring frost
Apr 18
First fall frost
Oct 24
Growing season
188 days
Hardiness zone
5b
Explore more for Illinois City, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Illinois City Dam 16, Il (5.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.