Portola Valley, CA 94060 Frost Dates
When can you plant in Portola Valley, CA?
The last spring frost here typically falls around 03/02, about 186 days from today. The first fall frost typically arrives around 11/25, about 268 frost-free days later.
Portola Valley sits in USDA Zone 9b (25 to 30°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 13 weeks of growing season left in Portola Valley before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Portola Valley's last frost
03/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/15 and you're betting against frost in roughly 9 years out of 10. 12/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Portola Valley compares
At roughly 268 frost-free days, Portola Valley places 5,764 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,988 of 2,555.
Learn more
local microclimates covers what one yard in Portola Valley can differ from the 94060 normal. zone vs. frost date covers why Zone 9b and Portola Valley's frost date answer different questions.