Frost dates in Hillsboro, OR
The average last spring frost in Hillsboro is around April 20 and the first fall frost is around October 25. That gives Hillsboro an average growing season of about 188 days.
Last spring frost
| Early (10% chance after) | March 27 |
|---|---|
| Average (50%) | April 20 |
| Late (90%) | May 10 |
First fall frost
| Early (10%) | October 5 |
|---|---|
| Average (50%) | October 25 |
| Late (90% chance before) | November 13 |