St. Helena, CA 95452 Frost Dates
When can you plant in St. Helena, CA?
Typically, the last spring freeze lands around 02/03, roughly 159 days out. The first fall frost typically arrives around 12/04, about 306 frost-free days later.
The USDA Plant Hardiness Zone Map puts St. Helena 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
About 14 weeks of growing season left in St. Helena before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around St. Helena's last frost
02/03 is the middle of 30 years of NOAA records, not a promise. Plant by 03/13 and you're betting against frost in roughly 9 years out of 10. 12/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Helena compares
At roughly 306 frost-free days, St. Helena places 3,692 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,500 of 2,555.
Learn more
the frost range covers how to read the range around St. Helena's dates instead of trusting one. local microclimates covers what one yard in St. Helena can differ from the 95452 normal.