Grass Valley, CA 95945 Frost Dates
Frost dates for Grass Valley, CA, ZIP 95945
Typically, the last spring freeze lands around 04/10, roughly 225 days out. The first fall frost typically arrives around 11/13, about 215 frost-free days later.
The USDA Plant Hardiness Zone Map puts Grass Valley in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 9a around Grass Valley has about 11 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
04/10 is the middle of 30 years of NOAA records, not a promise. Plant by 03/17 and you're betting against frost in roughly 9 years out of 10. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Grass Valley compares
At roughly 215 frost-free days, Grass Valley places 14,047 of 40,283 ZIP codes in this dataset. Within CA, it ranks 2,186 of 2,555.
Learn more
local microclimates explains what one yard in Grass Valley can differ from the 95945 normal, and zone vs. frost date explains why Zone 9a and Grass Valley's frost date answer different questions.