Fortuna, CA 95540 Frost Dates
Frost dates for Fortuna, CA, ZIP 95540
Typically, the last spring freeze lands around 03/04, roughly 188 days out. The first fall frost typically arrives around 11/22, about 264 frost-free days later.
The USDA Plant Hardiness Zone Map puts Fortuna 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 Fortuna has about 12 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 03/04 isn't a guarantee
03/04 is the middle of 30 years of NOAA records, not a promise. Plant by 01/27 and you're betting against frost in roughly 9 years out of 10. 04/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Fortuna compares
About 264 days separate Fortuna's last and first frost, putting it 6,058 of 40,283 ZIP codes nationally. Within CA, it ranks 2,002 of 2,555.
Learn more
the frost range explains how to read the range around Fortuna's dates instead of trusting one, and local microclimates explains what one yard in Fortuna can differ from the 95540 normal.