When to plant in Gresham, OR
USDA Zone 9aEverything below — frost dates, hardiness zone, and what to plant when in Gresham, Oregon — is derived from the closest NOAA station with complete climate normals.
With about 249 frost-free days, Gresham supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. In zone 9a, frost is a minor factor for Gresham — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
PORTLAND TROUTDALE 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 Gresham’s own odds, recorded at PORTLAND TROUTDALE AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 4 | Apr 19 | Mar 27 | Oct 11 | Oct 30 | Nov 22 |
| 32°F | Apr 12 | Mar 16 | Feb 18 | Oct 30 | Nov 20 | Dec 17 |
| 28°F | Mar 10 | Feb 14 | Dec 27 | Nov 15 | Dec 15 | Feb 3 |
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 Gresham, 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.
Gresham planting FAQ
When is the last spring frost in Gresham, OR?
On average, the last spring frost in Gresham is around March 16 (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 Gresham, OR?
Expect Gresham's first fall frost near November 20 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Gresham in?
Gresham is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Gresham?
Gresham has about 249 frost-free days — a long growing season — between the average last spring frost (March 16) and first fall frost (November 20).
When should I plant tomatoes in Gresham?
For Gresham, sow tomatoes indoors about January 19–February 2 and move the seedlings out around March 23, after the last spring frost.
Never miss a window in Gresham
An email when it’s time to start seeds, transplant, and sow — timed to Gresham’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at PORTLAND TROUTDALE AP, 6 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 Gresham, OR — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00024242. Retrieved from https://blissgarden.com/oregon/gresham.