Porterville, CA 93260 Frost Dates
Frost dates for Porterville, CA, ZIP 93260
The last spring frost here typically falls around 05/11, about 256 days from today. The first fall frost typically arrives around 10/17, about 155 frost-free days later.
Porterville sits in USDA Zone 9a (20 to 25°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.
What to do before the first frost
Zone 9a around Porterville has about 7 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 05/11 isn't a guarantee
05/11 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 06/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Porterville compares
Porterville's growing season runs about 155 days, ranking 33,911 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,425 of 2,555.
Learn more
the frost range explains how to read the range around Porterville's dates instead of trusting one, and local microclimates explains what one yard in Porterville can differ from the 93260 normal.