Knoxville, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Knoxville, a city in Knox County, Illinois.
This Afternoon
78°F
Mostly Sunny
Mostly sunny, with a high near 78. East southeast wind around 9 mph, with gusts as high as 16 mph.
7-day forecast for Knoxville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 78°F | Mostly Sunny | 9 mph ESE | 7% |
| Tonight | 68°F | Partly Cloudy then Chance Showers And Thunderstorms | 9 mph ESE | 29% |
| Saturday | 85°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 9 mph S | 37% |
| Saturday Night | 66°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 8 mph NNE | 72% |
| Sunday | 75°F | Showers And Thunderstorms Likely | 5 to 14 mph NNE | 74% |
| Sunday Night | 58°F | Showers And Thunderstorms Likely | 12 to 15 mph NE | 67% |
| Monday | 66°F | Showers And Thunderstorms Likely | 13 to 16 mph ENE | 67% |
| Monday Night | 53°F | Chance Rain Showers | 10 to 15 mph NE | 45% |
| Tuesday | 64°F | Chance Rain Showers | 10 to 14 mph NE | 33% |
| Tuesday Night | 49°F | Mostly Cloudy | 5 to 10 mph NNE | 4% |
| Wednesday | 68°F | Partly Sunny | 8 mph NNE | 2% |
| Wednesday Night | 52°F | Partly Cloudy | 1 to 6 mph NNE | 2% |
| Thursday | 69°F | Mostly Sunny | 1 to 6 mph NNE | 4% |
| Thursday Night | 54°F | Partly Cloudy | 3 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Knoxville (40.907, -90.286). Updated through the day.
Growing snapshot for Knoxville
Last spring frost
Apr 21
First fall frost
Oct 20
Growing season
181 days
Hardiness zone
5b
More local growing data for Knoxville: nearby ZIP 61430 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Knoxville, Il (3.1 mi from Knoxville). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.