Porterville, CA 93258 Frost Dates
Porterville, CA: when does the frost end?
Around 02/20 is the usual last spring frost, about 176 days away. Fall's first freeze usually shows up around 11/30, roughly 284 days after the last spring frost.
Zone 9b (25 to 30°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Porterville, not a forecast for this year.
Stretching the season past the first frost
With roughly 13 weeks until Porterville's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
02/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/26 and only about 1 year in 10 sees frost after that.
Porterville against the rest of the dataset
Porterville's growing season runs about 284 days, ranking 4,672 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,729 of 2,555.
Learn more
Before leaning on 93258's figures: local microclimates explains what one yard in Porterville can differ from the 93258 normal, while zone vs. frost date explains why Zone 9b and Porterville's frost date answer different questions.