When to plant in Mill Creek, WA
USDA Zone 8bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Mill Creek, Washington — all computed from Mill Creek's nearest NOAA weather station.
A generous ~253-day season lets Mill Creek gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. In zone 8b, Mill Creek supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
EVERETT SNOHOMISH AP · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Mill Creek’s own odds, recorded at EVERETT SNOHOMISH AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 27 | Apr 3 | Mar 15 | Oct 19 | Nov 2 | Nov 20 |
| 32°F | Mar 29 | Mar 9 | Feb 15 | Oct 31 | Nov 17 | Dec 7 |
| 28°F | Mar 9 | Feb 13 | Jan 1 | Nov 15 | Dec 6 | Jan 8 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Mill Creek, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 16 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Mill Creek planting FAQ
When is the last spring frost in Mill Creek, WA?
On average, the last spring frost in Mill Creek is around March 9 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Mill Creek, WA?
The first fall frost in Mill Creek typically arrives around November 17 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Mill Creek in?
Mill Creek is in USDA hardiness zone 8b. In zone 8b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Mill Creek?
Mill Creek has about 253 frost-free days — a long growing season — between the average last spring frost (March 9) and first fall frost (November 17).
When should I plant tomatoes in Mill Creek?
For Mill Creek, sow tomatoes indoors about January 12–January 26 and move the seedlings out around March 16, after the last spring frost.
Never miss a window in Mill Creek
An email when it’s time to start seeds, transplant, and sow — timed to Mill Creek’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Martha Lake · 3 km
- Lake Stickney · 3 km
- Mill Creek East · 4 km
- Eastmont · 4 km
- Silver Firs · 5 km
- North Lynnwood · 5 km
- Bothell East · 7 km
- Bothell West · 7 km
Frost dates recorded at EVERETT SNOHOMISH AP, 7 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Mill Creek, WA — Frost Dates & Zone 8b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00024222. Retrieved from https://blissgarden.com/washington/mill-creek.