San Rafael, CA 94901 Frost Dates
94901, near San Rafael, CA: the frost window
Around 01/16 is the usual last spring frost, about 141 days away. Fall's first freeze usually shows up around 12/18, roughly 334 days after the last spring frost.
San Rafael sits in USDA Zone 10a (30 to 35°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
San Rafael's growing season runs out in roughly 16 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 01/16 isn't a guarantee
01/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/21 and only about 1 year in 10 sees frost after that.
San Rafael against the rest of the dataset
At roughly 334 frost-free days, San Rafael places 2,761 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,252 of 2,555.
Learn more
Two guides worth reading on 94901: local microclimates, on what one yard in San Rafael can differ from the 94901 normal, and zone vs. frost date, on why Zone 10a and San Rafael's frost date answer different questions.