When to plant in Cedar Mill, OR
USDA Zone 8bCedar Mill, Oregon frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
With about 297 frost-free days, Cedar Mill supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. In zone 8b, Cedar Mill supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
NATURE PARK-BEAVERTON · 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 Cedar Mill’s own odds, recorded at NATURE PARK-BEAVERTON.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Mar 23 | Feb 25 | Oct 26 | Nov 13 | Dec 4 |
| 32°F | Mar 5 | Feb 11 | Dec 26 | Nov 11 | Dec 5 | Jan 12 |
| 28°F | Feb 16 | Jan 6 | Dec 2 | Nov 24 | Dec 21 | Feb 5 |
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 Cedar Mill, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 9 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.
Cedar Mill planting FAQ
When is the last spring frost in Cedar Mill, OR?
Plan for the last spring frost in Cedar Mill around February 11 (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 Cedar Mill, OR?
Expect Cedar Mill's first fall frost near December 5 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Cedar Mill in?
Cedar Mill is in USDA hardiness zone 8b. In zone 8b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Cedar Mill?
Cedar Mill has about 297 frost-free days — a long growing season — between the average last spring frost (February 11) and first fall frost (December 5).
When should I plant tomatoes in Cedar Mill?
For Cedar Mill, sow tomatoes indoors about December 17–December 31 and move the seedlings out around February 18, after the last spring frost.
Never miss a window in Cedar Mill
An email when it’s time to start seeds, transplant, and sow — timed to Cedar Mill’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at NATURE PARK-BEAVERTON, 5 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 Cedar Mill, OR — Frost Dates & Zone 8b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00355945. Retrieved from https://blissgarden.com/oregon/cedar-mill.