San Jose, CA 95138 Frost Dates
Frost dates for San Jose, CA, ZIP 95138
The last spring frost here typically falls around 05/03, about 248 days from today. The first fall frost typically arrives around 11/18, about 197 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 12 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 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/07 and you're betting against frost in roughly 9 years out of 10. 06/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Jose compares
San Jose's growing season runs about 197 days, ranking 18,570 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,245 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and San Jose's frost date answer different questions, and the frost range explains how to read the range around San Jose's dates instead of trusting one.