When to plant in Troutdale, OR
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Troutdale, Oregon — all computed from Troutdale's nearest NOAA weather station.
Zone 9a is warm enough that Troutdale can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
TROUTDALE · 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 Troutdale’s own odds, recorded at TROUTDALE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 9 | Apr 24 | Apr 3 | Oct 11 | Oct 30 | Nov 21 |
| 32°F | Apr 21 | Mar 26 | Feb 27 | Oct 26 | Nov 17 | Dec 10 |
| 28°F | Mar 21 | Feb 22 | Jan 15 | Nov 14 | Dec 7 | Jan 11 |
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 Troutdale, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 12 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.
Troutdale planting FAQ
When is the last spring frost in Troutdale, OR?
On average, the last spring frost in Troutdale is around March 26 (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 Troutdale, OR?
Expect Troutdale's first fall frost near November 17 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Troutdale in?
Troutdale is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Troutdale?
There are roughly 236 frost-free days in Troutdale (a long growing season), running from the average last frost around March 26 to the first fall frost near November 17.
When should I plant tomatoes in Troutdale?
In Troutdale, start tomato seeds indoors around January 29–February 12, then transplant seedlings outdoors around April 2 once the danger of frost has passed.
Never miss a window in Troutdale
An email when it’s time to start seeds, transplant, and sow — timed to Troutdale’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at TROUTDALE, 2 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 Troutdale, OR — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00358634. Retrieved from https://blissgarden.com/oregon/troutdale.