Frost dates in Zion, IL
The average last spring frost in Zion is around May 4 and the first fall frost is around October 18. That gives Zion an average growing season of about 167 days.
Last spring frost
| Early (10% chance after) | April 21 |
|---|---|
| Average (50%) | May 4 |
| Late (90%) | June 11 |
First fall frost
| Early (10%) | September 21 |
|---|---|
| Average (50%) | October 18 |
| Late (90% chance before) | October 29 |