Frost dates in Knoxville, IA
The average last spring frost in Knoxville is around April 22 and the first fall frost is around October 12. That gives Knoxville an average growing season of about 173 days.
Last spring frost
| Early (10% chance after) | April 6 |
|---|---|
| Average (50%) | April 22 |
| Late (90%) | May 7 |
First fall frost
| Early (10%) | September 27 |
|---|---|
| Average (50%) | October 12 |
| Late (90% chance before) | October 29 |