Frost dates in Harrisburg, IL
The average last spring frost in Harrisburg is around April 12 and the first fall frost is around October 19. That gives Harrisburg an average growing season of about 190 days.
Last spring frost
| Early (10% chance after) | March 25 |
|---|---|
| Average (50%) | April 12 |
| Late (90%) | April 26 |
First fall frost
| Early (10%) | October 4 |
|---|---|
| Average (50%) | October 19 |
| Late (90% chance before) | November 5 |