Mill Valley, CA 94147 Frost Dates
Mill Valley, CA: when does the frost end?
The last spring frost here typically falls around 12/30, about 124 days from today. Fall's first freeze usually shows up around 12/25, roughly 365 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Mill Valley in Zone 10b (35 to 40°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 17 weeks until Mill Valley's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 12/30 isn't a guarantee
12/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/13 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/02 and only about 1 year in 10 sees frost after that.
Mill Valley against the rest of the dataset
At roughly 365 frost-free days, Mill Valley places 1,662 of 40,283 ZIP codes in this dataset. Within CA, it ranks 807 of 2,555.
Learn more
Before leaning on 94147's figures: local microclimates explains what one yard in Mill Valley can differ from the 94147 normal, while zone vs. frost date explains why Zone 10b and Mill Valley's frost date answer different questions.