Mount Vernon, OR 97865 Frost Dates
Frost dates for Mount Vernon, OR, ZIP 97865
Around 05/28 is the usual last spring frost, about 273 days away. The first fall frost typically arrives around 09/18, about 113 frost-free days later.
The USDA Plant Hardiness Zone Map puts Mount Vernon in Zone 6b (-5 to 0°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 6b around Mount Vernon has about 3 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
05/28 is the middle of 30 years of NOAA records, not a promise. Plant by 05/12 and you're betting against frost in roughly 9 years out of 10. 06/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mount Vernon compares
About 113 days separate Mount Vernon's last and first frost, putting it 39,404 of 40,283 ZIP codes nationally. Within OR, it ranks 398 of 463.
Learn more
local microclimates explains what one yard in Mount Vernon can differ from the 97865 normal, and zone vs. frost date explains why Zone 6b and Mount Vernon's frost date answer different questions.