San Jose, CA 95123 Frost Dates
Frost dates for San Jose, CA, ZIP 95123
Around 02/02 is the usual last spring frost, about 158 days away. The first fall frost typically arrives around 12/06, about 310 frost-free days later.
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 San Jose, not a forecast for this year.
What to do before the first frost
Zone 9b around San Jose has about 14 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 02/02 isn't a guarantee
02/02 is the middle of 30 years of NOAA records, not a promise. Plant by 03/14 and you're betting against frost in roughly 9 years out of 10. 12/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Jose compares
About 310 days separate San Jose's last and first frost, putting it 3,546 of 40,283 ZIP codes nationally. Within CA, it ranks 1,468 of 2,555.
Learn more
the frost range explains how to read the range around San Jose's dates instead of trusting one, and local microclimates explains what one yard in San Jose can differ from the 95123 normal.