Knoxville, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Knoxville, a city in Marion County, Iowa.
Today
82°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Partly sunny. High near 82, with temperatures falling to around 80 in the afternoon. West southwest wind 6 to 9 mph. Chance of precipitation is 50%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Knoxville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 82°F | Chance Showers And Thunderstorms | 6 to 9 mph WSW | 50% |
| Tonight | 64°F | Showers And Thunderstorms Likely | 8 mph NNW | 66% |
| Sunday | 67°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 8 to 13 mph NNE | 48% |
| Sunday Night | 58°F | Slight Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 13 mph NE | 61% |
| Monday | 62°F | Rain Showers Likely | 13 mph NE | 61% |
| Monday Night | 52°F | Rain Showers Likely | 10 mph NE | 60% |
| Tuesday | 60°F | Slight Chance Rain Showers then Partly Sunny | 9 mph NE | 17% |
| Tuesday Night | 48°F | Partly Cloudy | 3 to 8 mph NE | 3% |
| Wednesday | 64°F | Sunny | 6 mph ENE | 1% |
| Wednesday Night | 53°F | Partly Cloudy | 5 mph E | 4% |
| Thursday | 66°F | Slight Chance Rain Showers | 5 mph E | 18% |
| Thursday Night | 56°F | Mostly Cloudy | 3 mph E | 7% |
| Friday | 68°F | Partly Sunny | 2 to 6 mph E | 7% |
| Friday Night | 57°F | Mostly Cloudy | 5 mph ESE | 7% |
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 Sep 19, 2026.