Portola, CA 95971 Frost Dates
When can you plant in Portola, CA?
Around 05/22 is the usual last spring frost, about 267 days away. The first fall frost typically arrives around 09/25, about 122 frost-free days later.
The USDA Plant Hardiness Zone Map puts Portola in Zone 7b (5 to 10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 4 weeks of growing season left in Portola before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
05/22 is the middle of 30 years of NOAA records, not a promise. Plant by 05/03 and you're betting against frost in roughly 9 years out of 10. 06/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Portola compares
Portola's growing season runs about 122 days, ranking 38,943 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,489 of 2,555.
Learn more
local microclimates covers what one yard in Portola can differ from the 95971 normal. zone vs. frost date covers why Zone 7b and Portola's frost date answer different questions.