San Jose, CA 95139 Frost Dates
95139, near San Jose, CA: the frost window
Around 05/03 is the usual last spring frost, about 248 days away. Fall's first freeze usually shows up around 11/18, roughly 197 days after the last spring frost.
San Jose 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 Jose's growing season runs out in roughly 12 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
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/05 and only about 1 year in 10 sees frost after that.
San Jose against the rest of the dataset
About 197 days separate San Jose's last and first frost, putting it 18,571 of 40,283 ZIP codes nationally. Within CA, it ranks 2,246 of 2,555.
Learn more
Two guides worth reading on 95139: the frost range, on how to read the range around San Jose's dates instead of trusting one, and local microclimates, on what one yard in San Jose can differ from the 95139 normal.