When to plant in Hermiston, OR
USDA Zone 7bEverything below — frost dates, hardiness zone, and what to plant when in Hermiston, Oregon — is derived from the closest NOAA station with complete climate normals.
In zone 7b, Hermiston supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
HERMISTON MUNI 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 Hermiston’s own odds, recorded at HERMISTON MUNI AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 22 | May 8 | Apr 26 | Sep 12 | Sep 28 | Oct 12 |
| 32°F | May 10 | Apr 26 | Apr 9 | Sep 25 | Oct 10 | Oct 26 |
| 28°F | Apr 29 | Apr 9 | Mar 20 | Oct 4 | Oct 24 | Nov 7 |
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 Hermiston, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 11 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.
Hermiston planting FAQ
When is the last spring frost in Hermiston, OR?
On average, the last spring frost in Hermiston is around April 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 Hermiston, OR?
Expect Hermiston's first fall frost near October 10 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Hermiston in?
Hermiston is in USDA hardiness zone 7b. In zone 7b, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Hermiston?
Hermiston has about 167 frost-free days — a moderate growing season — between the average last spring frost (April 26) and first fall frost (October 10).
When should I plant tomatoes in Hermiston?
For Hermiston, sow tomatoes indoors about March 1–March 15 and move the seedlings out around May 3, after the last spring frost.
Never miss a window in Hermiston
An email when it’s time to start seeds, transplant, and sow — timed to Hermiston’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Pendleton · 40 km
- Kennewick · 41 km
- Pasco · 50 km
- Richland · 50 km
- West Richland · 54 km
- Grandview · 66 km
- Sunnyside · 77 km
- Walla Walla · 78 km
Frost dates recorded at HERMISTON MUNI AP, 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 Hermiston, OR — Frost Dates & Zone 7b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00004113. Retrieved from https://blissgarden.com/oregon/hermiston.