San Bruno, CA 94080 Frost Dates
Frost dates for San Bruno, CA, ZIP 94080
Typically, the last spring freeze lands around 12/29, roughly 123 days out. The first fall frost typically arrives around 12/26, about 365 frost-free days later.
Zone 10a (30 to 35°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 Bruno, not a forecast for this year.
What to do before the first frost
Zone 10a around San Bruno has about 17 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.
The actual range around San Bruno's last frost
12/29 is the middle of 30 years of NOAA records, not a promise. Plant by 01/13 and you're betting against frost in roughly 9 years out of 10. 12/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Bruno compares
San Bruno's growing season runs about 365 days, ranking 960 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 404 of 2,555.
Learn more
zone vs. frost date explains why Zone 10a and San Bruno's frost date answer different questions, and the frost range explains how to read the range around San Bruno's dates instead of trusting one.