Larkspur, CA 94939 Frost Dates
Frost dates for Larkspur, CA, ZIP 94939
Typically, the last spring freeze lands around 01/16, roughly 141 days out. The first fall frost typically arrives around 12/18, about 334 frost-free days later.
The USDA Plant Hardiness Zone Map puts Larkspur in Zone 10a (30 to 35°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 10a around Larkspur has about 16 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 01/16 isn't a guarantee
01/16 is the middle of 30 years of NOAA records, not a promise. Plant by 02/25 and you're betting against frost in roughly 9 years out of 10. 12/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Larkspur compares
About 334 days separate Larkspur's last and first frost, putting it 2,792 of 40,283 ZIP codes nationally. Within CA, it ranks 1,276 of 2,555.
Learn more
local microclimates explains what one yard in Larkspur can differ from the 94939 normal, and zone vs. frost date explains why Zone 10a and Larkspur's frost date answer different questions.