San Ramon, CA 94597 Frost Dates
When can you plant in San Ramon, CA?
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.
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 Ramon, not a forecast for this year.
What to do before the first frost
About 17 weeks of growing season left in San Ramon before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
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
At roughly 282 frost-free days, San Ramon places 4,756 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,754 of 2,555.
Learn more
local microclimates covers what one yard in San Ramon can differ from the 94597 normal. zone vs. frost date covers why Zone 9b and San Ramon's frost date answer different questions.