San Bruno, CA 94066 Frost Dates
Frost dates for San Bruno, CA, ZIP 94066
Around 12/29 is the usual last spring frost, about 123 days away. The first fall frost typically arrives around 12/26, about 365 frost-free days later.
San Bruno sits in USDA Zone 10a (30 to 35°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 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
About 365 days separate San Bruno's last and first frost, putting it 959 of 40,283 ZIP codes nationally. Within CA, it ranks 403 of 2,555.
Learn more
local microclimates explains what one yard in San Bruno can differ from the 94066 normal, and zone vs. frost date explains why Zone 10a and San Bruno's frost date answer different questions.