Concord, CA 94521 Frost Dates
94521, near Concord, CA: the frost window
The last spring frost here typically falls around 01/09, about 134 days from today. Fall's first freeze usually shows up around 12/14, roughly 343 days after the last spring frost.
Zone 9b (25 to 30°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 Concord, not a forecast for this year.
Stretching the season past the first frost
Concord's growing season runs out in roughly 15 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
01/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/16 and only about 1 year in 10 sees frost after that.
Concord against the rest of the dataset
Concord's growing season runs about 343 days, ranking 2,463 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,109 of 2,555.
Learn more
Two guides worth reading on 94521: the frost range, on how to read the range around Concord's dates instead of trusting one, and local microclimates, on what one yard in Concord can differ from the 94521 normal.