Knoxville, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Knoxville, a city in Marion County, Iowa.
Overnight
66°F
Partly Cloudy
Partly cloudy, with a low around 66. South wind around 6 mph.
7-day forecast for Knoxville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 66°F | Partly Cloudy | 6 mph S | 1% |
| Tuesday | 86°F | Partly Sunny then Chance Showers And Thunderstorms | 5 to 8 mph WSW | 25% |
| Tuesday Night | 64°F | Showers And Thunderstorms | 7 to 10 mph NNE | 92% |
| Wednesday | 75°F | Showers And Thunderstorms Likely | 8 mph NNE | 92% |
| Wednesday Night | 59°F | Showers And Thunderstorms Likely | 3 to 8 mph NNE | 55% |
| Thursday | 81°F | Mostly Sunny | 5 mph NE | 12% |
| Thursday Night | 62°F | Mostly Clear | 3 mph SE | 3% |
| Friday | 86°F | Sunny | 2 to 7 mph S | 6% |
| Friday Night | 67°F | Mostly Clear | 6 mph SSE | 14% |
| Saturday | 89°F | Sunny | 5 to 9 mph S | 10% |
| Saturday Night | 72°F | Mostly Clear | 12 mph SSW | 13% |
| Sunday | 91°F | Mostly Sunny | 13 mph SSW | 13% |
| Sunday Night | 72°F | Slight Chance Showers And Thunderstorms | 12 mph S | 27% |
| Monday | 91°F | Chance Showers And Thunderstorms then Mostly Sunny | 10 to 14 mph SSW | 27% |
Forecast source: National Weather Service (api.weather.gov) for Knoxville (41.318, -93.103). Updated through the day.
Growing snapshot for Knoxville
Last spring frost
Apr 20
First fall frost
Oct 19
Growing season
180 days
Hardiness zone
5b
More local growing data for Knoxville: nearby ZIP 50138 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Knoxville, Ia (1.5 mi from Knoxville). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.