Mill Creek, WA 98296 Frost Dates
98296, near Mill Creek, WA: the frost window
Typically, the last spring freeze lands around 04/17, roughly 232 days out. Fall's first freeze usually shows up around 10/23, roughly 188 days after the last spring frost.
Mill Creek sits in USDA Zone 8b (15 to 20°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.
Stretching the season past the first frost
Mill Creek's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Mill Creek's last frost
04/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/07 and only about 1 year in 10 sees frost after that.
Mill Creek against the rest of the dataset
At roughly 188 frost-free days, Mill Creek places 21,868 of 40,283 ZIP codes in this dataset. Within WA, it ranks 405 of 700.
Learn more
Two guides worth reading on 98296: local microclimates, on what one yard in Mill Creek can differ from the 98296 normal, and zone vs. frost date, on why Zone 8b and Mill Creek's frost date answer different questions.