Frost dates in Ironton, MN
The average last spring frost in Ironton is around May 12 and the first fall frost is around September 29. That gives Ironton an average growing season of about 140 days.
Last spring frost
| Early (10% chance after) | April 24 |
|---|---|
| Average (50%) | May 12 |
| Late (90%) | May 22 |
First fall frost
| Early (10%) | September 12 |
|---|---|
| Average (50%) | September 29 |
| Late (90% chance before) | October 11 |