Santa Rosa, CA 95409 Frost Dates
Frost dates for Santa Rosa, CA, ZIP 95409
Around 02/25 is the usual last spring frost, about 181 days away. The first fall frost typically arrives around 12/01, about 279 frost-free days later.
The USDA Plant Hardiness Zone Map puts Santa Rosa 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 Santa Rosa has about 14 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
02/25 is the middle of 30 years of NOAA records, not a promise. Plant by 01/21 and you're betting against frost in roughly 9 years out of 10. 03/29 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Santa Rosa compares
Santa Rosa's growing season runs about 279 days, ranking 4,856 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,785 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and Santa Rosa's frost date answer different questions, and the frost range explains how to read the range around Santa Rosa's dates instead of trusting one.