Frost dates in Union, IA
The average last spring frost in Union is around April 28 and the first fall frost is around October 7. That gives Union an average growing season of about 162 days.
Last spring frost
| Early (10% chance after) | April 14 |
|---|---|
| Average (50%) | April 28 |
| Late (90%) | May 10 |
First fall frost
| Early (10%) | September 23 |
|---|---|
| Average (50%) | October 7 |
| Late (90% chance before) | October 21 |