Petaluma, CA 94999 Frost Dates
Petaluma, CA: when does the frost end?
Typically, the last spring freeze lands around 02/28, roughly 184 days out. Fall's first freeze usually shows up around 11/25, roughly 271 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Petaluma in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 13 weeks until Petaluma's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 02/28 isn't a guarantee
02/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/06 and only about 1 year in 10 sees frost after that.
Petaluma against the rest of the dataset
Petaluma's growing season runs about 271 days, ranking 5,416 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,872 of 2,555.
Learn more
Before leaning on 94999's figures: local microclimates explains what one yard in Petaluma can differ from the 94999 normal, while zone vs. frost date explains why Zone 9a and Petaluma's frost date answer different questions.