Frost dates in Promise City, IA
The average last spring frost in Promise City is around April 23 and the first fall frost is around October 14. That gives Promise City an average growing season of about 174 days.
Last spring frost
| Early (10% chance after) | April 9 |
|---|---|
| Average (50%) | April 23 |
| Late (90%) | May 4 |
First fall frost
| Early (10%) | September 28 |
|---|---|
| Average (50%) | October 14 |
| Late (90% chance before) | October 29 |