Frost dates in Portola Valley, CA
The average last spring frost in Portola Valley is around March 31 and the first fall frost is around December 4. That gives Portola Valley an average growing season of about 248 days.
Last spring frost
| Early (10% chance after) | February 8 |
|---|---|
| Average (50%) | March 31 |
| Late (90%) | April 14 |
First fall frost
| Early (10%) | November 12 |
|---|---|
| Average (50%) | December 4 |
| Late (90% chance before) | December 20 |