St. Helens, OR 97051 Frost Dates
Frost dates for St. Helens, OR, ZIP 97051
Around 04/18 is the usual last spring frost, about 233 days away. The first fall frost typically arrives around 11/07, about 201 frost-free days later.
Zone 8b (15 to 20°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 St. Helens, not a forecast for this year.
What to do before the first frost
Zone 8b around St. Helens 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.
Why 04/18 isn't a guarantee
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 03/20 and you're betting against frost in roughly 9 years out of 10. 05/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Helens compares
At roughly 201 frost-free days, St. Helens places 17,466 of 40,283 ZIP codes in this dataset. Within OR, it ranks 229 of 463.
Learn more
local microclimates explains what one yard in St. Helens can differ from the 97051 normal, and zone vs. frost date explains why Zone 8b and St. Helens's frost date answer different questions.