San Carlos, CA 94070 Frost Dates
94070, near San Carlos, CA: the frost window
Typically, the last spring freeze lands around 01/17, roughly 142 days out. Fall's first freeze usually shows up around 12/12, roughly 333 days after the last spring frost.
Zone 10a (30 to 35°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for San Carlos, not a forecast for this year.
Stretching the season past the first frost
San Carlos's growing season runs out in roughly 15 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 01/17 isn't a guarantee
01/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/16 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/20 and only about 1 year in 10 sees frost after that.
San Carlos against the rest of the dataset
About 333 days separate San Carlos's last and first frost, putting it 2,835 of 40,283 ZIP codes nationally. Within CA, it ranks 1,287 of 2,555.
Learn more
Two guides worth reading on 94070: zone vs. frost date, on why Zone 10a and San Carlos's frost date answer different questions, and the frost range, on how to read the range around San Carlos's dates instead of trusting one.