Frost dates in Mercer Island, WA
The average last spring frost in Mercer Island is around March 21 and the first fall frost is around November 10. That gives Mercer Island an average growing season of about 234 days.
Last spring frost
| Early (10% chance after) | February 25 |
|---|---|
| Average (50%) | March 21 |
| Late (90%) | April 17 |
First fall frost
| Early (10%) | October 29 |
|---|---|
| Average (50%) | November 10 |
| Late (90% chance before) | December 3 |