Sonora, CA 95327 Frost Dates
Frost dates for Sonora, CA, ZIP 95327
Typically, the last spring freeze lands around 04/09, roughly 224 days out. The first fall frost typically arrives around 11/09, about 213 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 Sonora, not a forecast for this year.
What to do before the first frost
Zone 9b around Sonora has about 10 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.
The actual range around Sonora's last frost
04/09 is the middle of 30 years of NOAA records, not a promise. Plant by 03/15 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 Sonora compares
About 213 days separate Sonora's last and first frost, putting it 14,493 of 40,283 ZIP codes nationally. Within CA, it ranks 2,197 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and Sonora's frost date answer different questions, and the frost range explains how to read the range around Sonora's dates instead of trusting one.