San Ramon, CA 94570 Frost Dates
94570, near San Ramon, CA: the frost window
Typically, the last spring freeze lands around 03/08, roughly 192 days out. Fall's first freeze usually shows up around 12/22, roughly 282 days after the last spring frost.
San Ramon sits in USDA Zone 9b (25 to 30°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 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.
How much risk comes with planting early here
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
San Ramon's growing season runs about 282 days, ranking 4,753 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,751 of 2,555.
Learn more
Two guides worth reading on 94570: the frost range, on how to read the range around San Ramon's dates instead of trusting one, and local microclimates, on what one yard in San Ramon can differ from the 94570 normal.