Frost dates in Jefferson, IA
The average last spring frost in Jefferson is around April 29 and the first fall frost is around October 5. That gives Jefferson an average growing season of about 159 days.
Last spring frost
| Early (10% chance after) | April 14 |
|---|---|
| Average (50%) | April 29 |
| Late (90%) | May 15 |
First fall frost
| Early (10%) | September 23 |
|---|---|
| Average (50%) | October 5 |
| Late (90% chance before) | October 22 |