Foster City, CA 94404 Frost Dates
When can you plant in Foster City, CA?
The last spring frost here typically falls around 01/17, about 142 days from today. The first fall frost typically arrives around 12/12, about 333 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 Foster City, not a forecast for this year.
What to do before the first frost
About 15 weeks of growing season left in Foster City before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Foster City's last frost
01/17 is the middle of 30 years of NOAA records, not a promise. Plant by 02/16 and you're betting against frost in roughly 9 years out of 10. 12/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Foster City compares
About 333 days separate Foster City's last and first frost, putting it 2,834 of 40,283 ZIP codes nationally. Within CA, it ranks 1,286 of 2,555.
Learn more
local microclimates covers what one yard in Foster City can differ from the 94404 normal. zone vs. frost date covers why Zone 10a and Foster City's frost date answer different questions.