USDA zone 8b in Oregon
USDA plant hardiness zone 8b covers 47 locations across Oregon (average annual extreme minimum 15 to 20 °F): Albany, OR, Aloha, OR, Alsea, OR, Beavercreek, OR, Blodgett, OR, Boring, OR, and 41 more. Average last spring frost across this group ranges February 25 (Portland) to May 20 (Grand Ronde), and growing seasons run 144–280 days (Vernonia to Portland) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Oregon location's own frost dates; the printable planting calendar uses Alsea, this group's median-season location.
- USDA zone
- 8b15 to 20 °F
- Last frost range
- Feb 25–May 20avg, 32°F
- First frost range
- Oct 1–Dec 3avg, 32°F
- Growing season range
- 144–280days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Albany | Corvallis, Tangent, Adair | Corvallis State Univ | Apr 17 | Oct 28 | 194 |
| Aloha | Cornelius, Cherry Grove, Banks | Forest Grove | Apr 16 | Oct 26 | 192 |
| Alsea * | — | Alsea Fh (fall Creek) | Apr 13 | Nov 3 | 202 |
| Beavercreek | Estacada | Estacada 2 Se | Mar 27 | Nov 14 | 230 |
| Blodgett | Peoria, Summit | Corvallis Water Bureau | May 15 | Oct 8 | 145 |
| Boring | Sandy | Headworks Portland Wtr B | Mar 27 | Nov 18 | 239 |
| Cascadia | — | Belknap Springs 8 N | May 5 | Oct 12 | 159 |
| Cascadia | Holley, Crawfordsville, Brownsville | Foster Dam | Apr 12 | Oct 28 | 197 |
| Cascadia | Marcola | Leaburg 1 Sw | Apr 3 | Nov 11 | 220 |
| Cloverdale | Beaver | Cloverdale | Mar 17 | Nov 22 | 251 |
| Cottage Grove | — | Cottage Grove Dam | Apr 12 | Nov 1 | 205 |
| Cottage Grove | Oakland, Yoncalla, Drain | Drain | Apr 16 | Oct 25 | 193 |
| Crabtree | Scio, Waterloo | Lacomb 3 Nne | Apr 26 | Oct 24 | 184 |
| Creswell | — | Cottage Grove 2e | Apr 24 | Oct 25 | 183 |
| Damascus | Mulino, Happy Valley | Oregon City | Mar 18 | Nov 18 | 244 |
| Days Creek | Shady Cove | Lost Creek Dam | Apr 29 | Oct 17 | 171 |
| Dillard | — | Roseburg Kqen | Mar 23 | Nov 18 | 237 |
| Eugene | Springfield, Veneta, River Road, Harrisburg, Elmira, Coburg, +3 more | Eugene Mahlon Sweet Ap | Apr 11 | Oct 23 | 196 |
| Glide | — | Idleyld Park 4 Ne | Apr 27 | Oct 19 | 176 |
| Glide | — | Toketee Falls | Apr 29 | Oct 18 | 171 |
| Grand Ronde | Fort Hill, Falls | Laurel Mtn | May 20 | Oct 23 | 157 |
| Halsey | — | Corvallis 10 Ssw | Apr 11 | Oct 30 | 203 |
| Hillsboro | Bull Mountain | Portland-hillsboro Ap | Apr 16 | Oct 23 | 191 |
| Jasper | Lowell | Lookout Pt Dam | Mar 7 | Nov 27 | 263 |
| Keizer | Dallas, Monmouth, Sheridan, Rickreall | Dallas 2 Ne | Apr 16 | Nov 1 | 199 |
| Keizer | Silverton, Molalla, Mount Angel, Gervais, Scotts Mills, Labish | Silverton | Mar 28 | Nov 10 | 227 |
| McMinnville | Newberg, Dundee, Lafayette, Carlton, Dayton, Amity, +1 more | Mcminnville Muni Ap | Apr 15 | Oct 26 | 195 |
| Medford | Central Point, Jacksonville, Gold Hill | Medford Rogue Vly Ap | Apr 8 | Oct 29 | 204 |
| Mill | Gates | Detroit Dam | Mar 9 | Dec 3 | 270 |
| Myrtle Creek | Days Creek, Canyonville, Riddle, Glendale | Riddle | Mar 31 | Nov 6 | 221 |
| Nehalem | — | Tillamook | Apr 22 | Oct 21 | 183 |
| Oakridge | Westfir | Oakridge Fish Hatchery | Apr 24 | Oct 24 | 183 |
| Phoenix | — | Ashland | May 6 | Oct 8 | 154 |
| Portland | Aloha, Cedar Mill, Oak Hills | Portland Kgw-tv | Feb 25 | Dec 1 | 280 |
| Portland | Camas, Orient | Portland Wfo | Mar 13 | Nov 22 | 251 |
| Roseburg North | — | Roseburg Rgnl Ap | Mar 19 | Nov 20 | 245 |
| Salem | Independence, Turner | Salem Mcnary Fld | Apr 3 | Nov 1 | 212 |
| Seaside | — | Seaside | Apr 2 | Nov 12 | 223 |
| Selma | O'Brien, Kerby | Cave Junction 1 Wnw | May 1 | Oct 12 | 161 |
| Shedd | — | Lebanon | Mar 14 | Nov 18 | 248 |
| Stayton | Four Corners, Marion, Aumsville, Sublimity, Jefferson, Mehama | Stayton | Mar 29 | Nov 6 | 222 |
| Sutherlin | Fair Oaks, Roseburg North | Winchester | Mar 31 | Nov 5 | 215 |
| Svensen | — | Astoria Rgnl Ap | Mar 26 | Nov 11 | 232 |
| Vernonia | — | Vernonia #2 | May 8 | Oct 1 | 144 |
| Williams | Selma, New Hope | Grants Pass | Apr 8 | Oct 28 | 201 |
| Wilsonville | Woodburn, Sherwood, Canby, Hubbard, Aurora, Donald, +1 more | Aurora State Ap | Mar 16 | Nov 14 | 242 |
| Wimer | Merlin, Glendale | Sexton Summit | May 16 | Oct 30 | 164 |
* Alsea is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Alsea, representative)
Computed from Alsea's average frost dates — the median-season location in this Oregonzone 8b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Feb 16 – Mar 2 | Apr 20 – Apr 27 | Jun 19 – Jul 9 | — | matures comfortably |
| Pepper | Very tender | Feb 2 – Feb 16 | Apr 27 – May 4 | Jun 26 – Jul 26 | — | matures comfortably |
| Cucumber | Tender | Mar 16 – Mar 23 | Apr 20 – Apr 27 | Jun 9 – Jun 29 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 20 – Apr 27 | Jun 4 – Jun 19 | — | matures comfortably |
| Bush bean | Tender | — | Apr 20 – Apr 27 | Jun 9 – Jun 19 | Sep 4 – Sep 14 | matures comfortably |
| Sweet corn | Tender | — | Apr 13 – Apr 27 | Jun 12 – Jul 12 | — | matures comfortably |
| Basil | Very tender | Mar 2 – Mar 16 | Apr 20 – Apr 27 | May 20 – Jun 4 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 2 – Mar 16 | Mar 16 – Mar 30 | Apr 30 – May 15 | Aug 21 – Sep 5 | matures comfortably |
| Pea | Hardy | — | Mar 2 – Mar 16 | Apr 26 – May 11 | Aug 11 – Aug 26 | matures comfortably |
| Spinach | Hardy | — | Mar 2 – Mar 16 | Apr 11 – Apr 21 | Aug 31 – Sep 10 | matures comfortably |
| Carrot | Half-hardy | — | Mar 23 – Mar 30 | May 22 – Jun 11 | Aug 1 – Aug 21 | matures comfortably |
| Broccoli | Half-hardy | Feb 16 – Mar 2 | Mar 16 – Mar 30 | May 10 – May 30 | Aug 6 – Aug 26 | matures comfortably |
Which crops fit this growing season
Using Alsea's own 202-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Alsea)
From NOAA's 1991–2020 Climate Normals at station USC00350145. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 7 | May 28 | Oct 11 | Nov 3 | 155 |
| 32°F (freeze) | Apr 13 | May 3 | Nov 3 | Dec 3 | 202 |
| 28°F | Feb 28 | Mar 31 | Nov 28 | Jan 4 | 272 |
| 24°F | Jan 12 | Feb 27 | Dec 18 | Feb 10 | 343 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 47 locations is 2,278; Alsea's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 1,498 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,006 | cool-season crops (brassicas, greens) |
Hardiness zone 8b in Oregon
Zone 8b means an average annual extreme minimum winter temperature of about 15 to 20 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Oregon spans 9 hardiness zones in this dataset — see all Oregon locations for the full range, including zones5b, 6a, 6b, 7a, 7b, 8a, 9a, 9b.
Explore zone 8b in other states at zone 8b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 8b mean in Oregon?
- Zone 8b means an average annual extreme minimum winter temperature of 15 to 20 °F — the standard USDA measure of which perennials survive winter. 47 locations in Oregon fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Oregon's zone 8b is the growing season longest?
- Portland runs the longest season on this page at about 280 days; Vernonia is shortest at about 144 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Oregon's zone 8b?
- Using Alsea's frost dates (this page's median-season location): start seeds indoors about Feb 16 – Mar 2, then transplant outside about Apr 20 – Apr 27. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Oregon's zone 8b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 47 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.