Frost dates in Marengo, IL
The average last spring frost in Marengo is around May 4 and the first fall frost is around October 5. That gives Marengo an average growing season of about 154 days.
Last spring frost
| Early (10% chance after) | April 19 |
|---|---|
| Average (50%) | May 4 |
| Late (90%) | May 19 |
First fall frost
| Early (10%) | September 24 |
|---|---|
| Average (50%) | October 5 |
| Late (90% chance before) | October 23 |