Vallejo, CA 94592 Frost Dates
Frost dates for Vallejo, CA, ZIP 94592
Typically, the last spring freeze lands around 03/05, roughly 189 days out. The first fall frost typically arrives around 11/21, about 256 frost-free days later.
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 Vallejo, not a forecast for this year.
What to do before the first frost
Zone 9b around Vallejo has about 12 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
03/05 is the middle of 30 years of NOAA records, not a promise. Plant by 01/26 and you're betting against frost in roughly 9 years out of 10. 04/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Vallejo compares
Vallejo's growing season runs about 256 days, ranking 6,784 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,062 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and Vallejo's frost date answer different questions, and the frost range explains how to read the range around Vallejo's dates instead of trusting one.