Frost dates in Winthrop, IA
The average last spring frost in Winthrop is around April 23 and the first fall frost is around October 5. That gives Winthrop an average growing season of about 165 days.
Last spring frost
| Early (10% chance after) | April 3 |
|---|---|
| Average (50%) | April 23 |
| Late (90%) | May 12 |
First fall frost
| Early (10%) | September 22 |
|---|---|
| Average (50%) | October 5 |
| Late (90% chance before) | October 22 |