Fairfield, CA 94533 Frost Dates
Frost dates for Fairfield, CA, ZIP 94533
Typically, the last spring freeze lands around 01/15, roughly 140 days out. The first fall frost typically arrives around 12/14, about 336 frost-free days later.
The USDA Plant Hardiness Zone Map puts Fairfield 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 Fairfield has about 15 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.
How much risk comes with planting early here
01/15 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. 12/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Fairfield compares
At roughly 336 frost-free days, Fairfield places 2,706 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,229 of 2,555.
Learn more
local microclimates explains what one yard in Fairfield can differ from the 94533 normal, and zone vs. frost date explains why Zone 9b and Fairfield's frost date answer different questions.