Walnut Creek, CA 94507 Frost Dates
94507, near Walnut Creek, 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.
Walnut Creek 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
Walnut Creek'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.
Walnut Creek against the rest of the dataset
About 282 days separate Walnut Creek's last and first frost, putting it 4,762 of 40,283 ZIP codes nationally. Within CA, it ranks 1,760 of 2,555.
Learn more
Two guides worth reading on 94507: the frost range, on how to read the range around Walnut Creek's dates instead of trusting one, and local microclimates, on what one yard in Walnut Creek can differ from the 94507 normal.