Portola, CA 95983 Frost Dates
Portola, CA: when does the frost end?
Around 05/22 is the usual last spring frost, about 267 days away. Fall's first freeze usually shows up around 09/25, roughly 122 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 4 weeks until Portola's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Portola's last frost
05/22 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/03 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/14 and only about 1 year in 10 sees frost after that.
Portola against the rest of the dataset
Portola's growing season runs about 122 days, ranking 38,944 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,490 of 2,555.
Learn more
Before leaning on 95983's figures: the frost range explains how to read the range around Portola's dates instead of trusting one, while local microclimates explains what one yard in Portola can differ from the 95983 normal.