Porterville, CA 93270 Frost Dates
93270, near Porterville, CA: the frost window
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.
Porterville 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.
Stretching the season past the first frost
Porterville's growing season runs out in roughly 13 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
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
At roughly 284 frost-free days, Porterville places 4,674 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,731 of 2,555.
Learn more
Two guides worth reading on 93270: the frost range, on how to read the range around Porterville's dates instead of trusting one, and local microclimates, on what one yard in Porterville can differ from the 93270 normal.