Morton, WA 98356 Frost Dates
Frost dates for Morton, WA, ZIP 98356
Typically, the last spring freeze lands around 04/07, roughly 222 days out. The first fall frost typically arrives around 11/13, about 215 frost-free days later.
The USDA Plant Hardiness Zone Map puts Morton in Zone 8b (15 to 20°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 8b around Morton has about 11 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 Morton's last frost
04/07 is the middle of 30 years of NOAA records, not a promise. Plant by 03/16 and you're betting against frost in roughly 9 years out of 10. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Morton compares
Morton's growing season runs about 215 days, ranking 14,135 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 255 of 700.
Learn more
zone vs. frost date explains why Zone 8b and Morton's frost date answer different questions, and the frost range explains how to read the range around Morton's dates instead of trusting one.