San Ramon, CA 94808 Frost Dates
94808, near San Ramon, CA: the frost window
Around 03/08 is the usual last spring frost, about 192 days away. Fall's first freeze usually shows up around 12/22, roughly 282 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts San Ramon in Zone 10a (30 to 35°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
San Ramon's growing season runs out in roughly 17 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around San Ramon's last frost
03/08 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/15 and only about 1 year in 10 sees frost after that.
San Ramon against the rest of the dataset
At roughly 282 frost-free days, San Ramon places 4,759 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,757 of 2,555.
Learn more
Two guides worth reading on 94808: local microclimates, on what one yard in San Ramon can differ from the 94808 normal, and zone vs. frost date, on why Zone 10a and San Ramon's frost date answer different questions.