Oregon growing regions
Oregon runs from zone 5b to 9b, and its last spring frost moves ten weeks between the coast and the Klamath Basin. There is no such thing as an Oregon planting calendar. There are seven of them.
Built from 474 Oregon ZIP codes carrying the 2023 USDA hardiness map, and 24NOAA weather stations sampled one per hardiness zone per region. Every frost date below is read from the 1991–2020 normals by the same code behind the ZIP lookup, so the two cannot disagree.
Oregon Coast
Astoria · Tillamook · Newport
The mildest winters in Oregon: 49 of 72 coastal ZIPs are zone 9a and eleven reach 9b, the warmest in the state. Those 9b ZIPs run from Brookings to Pacific City rather than clustering in the south, so this is a coastal effect down the whole shore, not a southern one.
- Zones
- 8b–9b
- Season
- 198–255d
- ZIPs
- 72
Columbia Gorge
Hood River · The Dalles · Mosier
A river-cut corridor through the Cascades, running 7a to 8b across a few miles as the country dries out eastward. Orchard ground, and the smallest region here at seventeen ZIPs.
- Zones
- 7a–8b
- Season
- 133–270d
- ZIPs
- 17
Willamette Valley
Portland · Salem · Corvallis
Where most of Oregon lives and most of it gardens: 212 ZIPs, 45 per cent of every ZIP in the state. Seven in ten are zone 8b, with 60 more in a warmer 9a.
- Zones
- 8a–9a
- Season
- 191–244d
- ZIPs
- 212
Umpqua & Rogue Valleys
Roseburg · Grants Pass · Medford
The southern interior valleys, mostly 8b, reaching 9a around Roseburg and cooling to 8a around Ashland. The single 6b ZIP is Crater Lake on the eastern rim, which is a mountain rather than a valley and is why this region's raw band reads 6b to 9a.
- Zones
- 6b–9a
- Season
- 198–236d
- ZIPs
- 42
Frost recorded in every month at 1 station
Klamath Basin & the Outback
Klamath Falls · Lakeview · Chiloquin
The clearest case in Oregon that latitude is not the variable. This is the southern edge of the state, and it runs 6a to 7a while Portland, two hundred miles north, sits at 8b and 9a. The basin is high ground, and elevation wins.
- Zones
- 6a–7a
- Season
- 126d
- ZIPs
- 21
Frost recorded in every month at 1 station
Central Oregon
Bend · Redmond · Madras
High desert east of the Cascade crest, 6a to 7b across 29 ZIPs. Bend, the largest town in the region, is 6b: two full zones colder than Eugene, on the other side of the Cascades.
- Zones
- 6a–7b
- Season
- 131–147d
- ZIPs
- 29
Frost recorded in every month at 2 stations
Eastern Oregon
Pendleton · La Grande · Baker City
The coldest ground in the state and the widest internal spread, 5b to 7b, taking in the Blue Mountains, the Wallowas and the warmer Snake River farmland on the Idaho line. Oregon's only 5b ZIP is here.
- Zones
- 5b–7b
- Season
- 130–180d
- ZIPs
- 81
Frost recorded in every month at 2 stations
Where the boundaries came from
The regions are drawn as boxes on a map and assigned by ZIP centroid, which means they are arguable. That is why every page prints how many ZIP codes its region holds: if you disagree with where a line falls, you can see the size of the thing being argued about.
What is not arguable is the spread. The coast holds the mildest winters in the state at zone 9a and 9b; Eastern Oregon holds the only 5b. Klamath Falls sits at the southern edge of Oregon and runs colder than Portland two hundred miles north, because the basin is high ground and elevation beats latitude.
Farm rooted clothing · Est. 2005
The guides are free. The shop is the business.
Sun & Rain Works is a small apparel outfit in Eugene, Oregon, with agricultural roots and a slow path toward farming. The oregon growing regions you just read comes from the same place as the shirts.