American Canyon, CA 94503 Frost Dates
Frost dates for American Canyon, CA, ZIP 94503
The last spring frost here typically falls around 03/05, about 189 days from today. The first fall frost typically arrives around 11/21, about 256 frost-free days later.
The USDA Plant Hardiness Zone Map puts American Canyon in Zone 9b (25 to 30°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 9b around American Canyon 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 American Canyon compares
About 256 days separate American Canyon's last and first frost, putting it 6,797 of 40,283 ZIP codes nationally. Within CA, it ranks 2,063 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and American Canyon's frost date answer different questions, and the frost range explains how to read the range around American Canyon's dates instead of trusting one.