Tukwila, WA 98178 Frost Dates
Frost dates for Tukwila, WA, ZIP 98178
The last spring frost here typically falls around 03/13, about 197 days from today. The first fall frost typically arrives around 11/17, about 247 frost-free days later.
Tukwila sits in USDA Zone 9a (20 to 25°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 9a around Tukwila has about 12 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 03/13 isn't a guarantee
03/13 is the middle of 30 years of NOAA records, not a promise. Plant by 02/20 and you're betting against frost in roughly 9 years out of 10. 04/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Tukwila compares
About 247 days separate Tukwila's last and first frost, putting it 7,799 of 40,283 ZIP codes nationally. Within WA, it ranks 153 of 700.
Learn more
zone vs. frost date explains why Zone 9a and Tukwila's frost date answer different questions, and the frost range explains how to read the range around Tukwila's dates instead of trusting one.