San Joaquin, CA 93627 Frost Dates
93627, near San Joaquin, CA: the frost window
Typically, the last spring freeze lands around 02/27, roughly 183 days out. Fall's first freeze usually shows up around 11/26, roughly 271 days after the last spring frost.
Zone 9a (20 to 25°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 Joaquin, not a forecast for this year.
Stretching the season past the first frost
San Joaquin's growing season runs out in roughly 13 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 02/27 isn't a guarantee
02/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/13 and only about 1 year in 10 sees frost after that.
San Joaquin against the rest of the dataset
San Joaquin's growing season runs about 271 days, ranking 5,435 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,889 of 2,555.
Learn more
Two guides worth reading on 93627: zone vs. frost date, on why Zone 9a and San Joaquin's frost date answer different questions, and the frost range, on how to read the range around San Joaquin's dates instead of trusting one.