San Ramon, CA 94506 Frost Dates
Frost dates for San Ramon, CA, ZIP 94506
The last spring frost here typically falls around 03/08, about 192 days from today. The first fall frost typically arrives around 12/22, about 282 frost-free days later.
The USDA Plant Hardiness Zone Map puts San Ramon in Zone 9b (25 to 30°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 9b around San Ramon 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.
Why 03/08 isn't a guarantee
03/08 is the middle of 30 years of NOAA records, not a promise. Plant by 01/12 and you're betting against frost in roughly 9 years out of 10. 04/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Ramon compares
About 282 days separate San Ramon's last and first frost, putting it 4,748 of 40,283 ZIP codes nationally. Within CA, it ranks 1,746 of 2,555.
Learn more
local microclimates explains what one yard in San Ramon can differ from the 94506 normal, and zone vs. frost date explains why Zone 9b and San Ramon's frost date answer different questions.