Portola, CA 96109 Frost Dates
When can you plant in Portola, CA?
Typically, the last spring freeze lands around 05/21, roughly 266 days out. The first fall frost typically arrives around 10/01, about 130 frost-free days later.
The USDA Plant Hardiness Zone Map puts Portola in Zone 7a (0 to 5°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 5 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
05/21 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 06/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Portola compares
Portola's growing season runs about 130 days, ranking 38,381 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,470 of 2,555.
Learn more
the frost range covers how to read the range around Portola's dates instead of trusting one. local microclimates covers what one yard in Portola can differ from the 96109 normal.