Illinois City, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Illinois City, a community in Rock Island County, Illinois.
This Afternoon
75°F
Mostly Sunny
Mostly sunny, with a high near 75. Southeast wind around 10 mph.
7-day forecast for Illinois City
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 75°F | Mostly Sunny | 10 mph SE | 6% |
| Tonight | 69°F | Mostly Cloudy then Chance Showers And Thunderstorms | 5 to 10 mph SE | 56% |
| Saturday | 84°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph S | 62% |
| Saturday Night | 65°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 mph N | 81% |
| Sunday | 72°F | Showers And Thunderstorms Likely | 5 to 15 mph NE | 78% |
| Sunday Night | 58°F | Showers And Thunderstorms Likely | 10 to 15 mph NE | 62% |
| Monday | 65°F | Rain Showers Likely | 15 mph NE | 57% |
| Monday Night | 54°F | Rain Showers Likely | 10 to 15 mph NE | 56% |
| Tuesday | 64°F | Chance Showers And Thunderstorms | 10 to 15 mph NE | 42% |
| Tuesday Night | 50°F | Partly Cloudy | 5 to 10 mph NE | 6% |
| Wednesday | 68°F | Mostly Sunny | 5 to 10 mph NE | 1% |
| Wednesday Night | 53°F | Partly Cloudy | 0 to 5 mph NE | 2% |
| Thursday | 70°F | Mostly Sunny | 5 mph NE | 5% |
| Thursday Night | 55°F | Partly Cloudy | 0 to 5 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov) for Illinois City (41.399, -90.900). Updated through the day.
Growing snapshot for Illinois City
Last spring frost
Apr 18
First fall frost
Oct 24
Growing season
188 days
Hardiness zone
5b
More local growing data for Illinois City: nearby ZIP 61259 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Andalusia
Barstow
Buffalo Prairie
Carbon Cliff
Coal Valley
Cordova
Coyne Center
East Moline
Edgington
Hampton
Hillsdale
Joslin
Milan
Moline
Oak Grove
Port Byron
Rapids City
Rock Island
Silvis
Taylor Ridge
Climate data from the nearest NOAA station, Illinois City Dam 16, Il (5.2 mi from Illinois City). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.