Coulee City, WA 99115 Frost Dates
Frost dates for Coulee City, WA, ZIP 99115
Typically, the last spring freeze lands around 05/02, roughly 247 days out. The first fall frost typically arrives around 10/12, about 162 frost-free days later.
The USDA Plant Hardiness Zone Map puts Coulee City 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 Coulee City has about 6 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
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/17 and you're betting against frost in roughly 9 years out of 10. 05/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Coulee City compares
About 162 days separate Coulee City's last and first frost, putting it 31,835 of 40,283 ZIP codes nationally. Within WA, it ranks 563 of 700.
Learn more
zone vs. frost date explains why Zone 6b and Coulee City's frost date answer different questions, and the frost range explains how to read the range around Coulee City's dates instead of trusting one.