When to plant in White Center, WA
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for White Center, Washington — all computed from White Center's nearest NOAA weather station.
A generous ~249-day season lets White Center gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. In zone 9a, frost is a minor factor for White Center — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
SEATTLE BOEING FLD · 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 White Center’s own odds, recorded at SEATTLE BOEING FLD.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 28 | Apr 3 | Mar 17 | Oct 17 | Oct 31 | Nov 17 |
| 32°F | Apr 1 | Mar 13 | Feb 20 | Nov 1 | Nov 17 | Dec 6 |
| 28°F | Mar 10 | Feb 18 | Jan 7 | Nov 12 | Dec 2 | Dec 30 |
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 White Center, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 10 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.
White Center planting FAQ
When is the last spring frost in White Center, WA?
Plan for the last spring frost in White Center around March 13 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in White Center, WA?
In White Center, the first 32°F freeze of fall lands around November 17 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is White Center in?
White Center is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in White Center?
White Center has about 249 frost-free days — a long growing season — between the average last spring frost (March 13) and first fall frost (November 17).
When should I plant tomatoes in White Center?
For White Center, sow tomatoes indoors about January 16–January 30 and move the seedlings out around March 20, after the last spring frost.
Never miss a window in White Center
An email when it’s time to start seeds, transplant, and sow — timed to White Center’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Burien · 4 km
- Tukwila · 7 km
- SeaTac · 8 km
- Bryn Mawr-Skyway · 8 km
- Mercer Island · 11 km
- Renton · 12 km
- Seattle · 12 km
- Des Moines · 14 km
Frost dates recorded at SEATTLE BOEING FLD, 4 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 White Center, WA — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00024234. Retrieved from https://blissgarden.com/washington/white-center.