Knoxville, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Knoxville, a city in Marion County, Iowa.
Overnight
46°F
Slight Chance Rain Showers
A slight chance of rain showers after 5am. Cloudy. Low around 46, with temperatures rising to around 48 overnight. West wind around 14 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.
7-day forecast for Knoxville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 46°F | Slight Chance Rain Showers | 14 mph W | 16% |
| Wednesday | 52°F | Slight Chance Rain Showers then Cloudy | 16 mph W | 18% |
| Wednesday Night | 44°F | Mostly Cloudy then Chance Rain Showers | 13 mph W | 28% |
| Thursday | 54°F | Chance Rain Showers | 12 mph NW | 32% |
| Thursday Night | 41°F | Mostly Cloudy | 9 mph NNW | 12% |
| Friday | 50°F | Partly Sunny | 5 to 8 mph N | 5% |
| Friday Night | 32°F | Partly Cloudy | 0 to 3 mph NNE | 2% |
| Saturday | 53°F | Mostly Sunny | 0 to 5 mph WSW | 1% |
| Saturday Night | 36°F | Mostly Clear | 5 mph WSW | 1% |
| Sunday | 59°F | Sunny | 6 mph W | 1% |
| Sunday Night | 38°F | Clear | 5 mph SW | 0% |
| Monday | 65°F | Sunny | 5 to 9 mph SW | 0% |
| Monday Night | 41°F | Clear | 6 mph W | 0% |
| Tuesday | 65°F | Sunny | 5 mph NW | 0% |
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 Nov 4, 2026.