USDA zone 8b in Washington
USDA plant hardiness zone 8b covers 53 locations across Washington (average annual extreme minimum 15 to 20 °F): Aberdeen, WA, Amanda Park, WA, Anacortes, WA, Bell Hill, WA, Bellevue, WA, Bellevue, WA, and 47 more. Average last spring frost across this group ranges February 26 (Friday Harbor) to May 22 (Eatonville), and growing seasons run 134–276 days (Eatonville to Friday Harbor) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Washington location's own frost dates; the printable planting calendar uses Ridgefield, this group's median-season location.
- USDA zone
- 8b15 to 20 °F
- Last frost range
- Feb 26–May 22avg, 32°F
- First frost range
- Oct 3–Nov 29avg, 32°F
- Growing season range
- 134–276days
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) |
|---|---|---|---|---|---|
| Aberdeen | — | Aberdeen | Mar 29 | Nov 15 | 234 |
| Amanda Park | Queets | Clearwater | Apr 29 | Oct 17 | 171 |
| Anacortes | Oak Harbor, Whidbey Island Station, La Conner | Whidbey Island Nas | Mar 13 | Nov 14 | 244 |
| Bell Hill | — | Sequim 2 E | Apr 21 | Oct 20 | 181 |
| Bellevue | — | Renton Muni Ap | Mar 13 | Nov 16 | 248 |
| Bellevue | Union Hill-Novelty Hill, Sammamish, Redmond, Bothell, Woodinville | Seattle Sand Pt Wsfo | Mar 8 | Nov 23 | 259 |
| Bellingham | Marietta-Alderwood | Bellingham 3 Ssw | Apr 1 | Nov 2 | 216 |
| Birch Bay | Point Roberts, Custer | Blaine | Mar 31 | Nov 4 | 219 |
| Bremerton | Silverdale, Bangor Base, Port Orchard, Brinnon, Belfair, Poulsbo, +4 more | Bremerton | Mar 29 | Nov 14 | 227 |
| Camano | Freeland, Coupeville | Coupeville 1 S | Mar 17 | Nov 11 | 237 |
| Chinook | — | Long Beach Exp Stn | Apr 6 | Oct 26 | 200 |
| Cottage Lake | Woods Creek, Three Lakes, Cathcart, Duvall, Lake Marcel-Stillwater | Monroe | Apr 17 | Oct 23 | 188 |
| Cougar | — | Cougar 6 E | Apr 1 | Nov 18 | 227 |
| Eatonville | — | Longmire Rainier Nps | May 22 | Oct 3 | 134 |
| Everett | Marysville, Lake Cassidy, Lake Goodwin | Everett | Mar 24 | Nov 2 | 223 |
| Ferndale | — | Bellingham Intl Ap | Mar 31 | Oct 30 | 211 |
| Forks | — | Forks 1 E | Apr 26 | Oct 25 | 182 |
| Friday Harbor | — | Olga 2 Se | Feb 26 | Nov 29 | 276 |
| Graham | South Hill, Puyallup, Parkland, Elk Plain, Bonney Lake, Sumner, +5 more | Mcmillin Rsvr | Apr 11 | Oct 30 | 202 |
| Hansville | Mukilteo, Eastmont, Mill Creek East, Clinton, Langley | Everett Snohomish Ap | Mar 9 | Nov 17 | 250 |
| Hobart | Issaquah, Mirrormont, Lake Holm, Black Diamond | Landsburg | Apr 20 | Oct 25 | 187 |
| Hockinson | Amboy, Lewisville, Orchards, Woodland, La Center, Yacolt | Battle Ground | Apr 26 | Oct 16 | 174 |
| Humptulips | Amanda Park, Aberdeen Gardens, Santiago | Humptulips Salmon Hatchery | Apr 26 | Oct 22 | 180 |
| Kelso | Longview Heights, Rainier, Castle Rock, Cougar, Deer Island, Ryderwood, +1 more | Longview | Apr 8 | Nov 5 | 210 |
| Kent | Auburn, East Renton Highlands, Covington, Fairwood | Kent | Mar 20 | Nov 10 | 233 |
| Lacey | Olympia, Nisqually Indian Community, Rainier, Tanglewilde, McKenna | Olympia Ap | Apr 29 | Oct 14 | 169 |
| Malone | Satsop, Elma, Aberdeen Gardens | Elma | May 1 | Oct 14 | 169 |
| Morton | — | Glenoma | Apr 24 | Oct 15 | 176 |
| Mount Vernon | Burlington, Clear Lake, Lake McMurray, Hamilton, Bow, Lyman, +1 more | Sedro-woolley | Mar 27 | Nov 6 | 224 |
| Naselle | — | Naselle 2 Ene | Apr 24 | Oct 20 | 179 |
| Neilton | — | Quinault 4 Ne | Apr 7 | Nov 10 | 214 |
| Onalaska | Morton, Mossyrock | Mayfield Pwr Plt | Apr 7 | Nov 13 | 215 |
| Port Angeles | Port Angeles East | Elwha Rs | Apr 9 | Nov 3 | 209 |
| Port Ludlow | Port Hadlock-Irondale, Freeland | Port Townsend | Mar 1 | Nov 28 | 274 |
| Port Ludlow | Quilcene | Quilcene 2 Sw | Apr 11 | Oct 28 | 199 |
| Prairie Heights | Wilkeson, Carbonado, South Prairie | Mud Mtn Dam | Apr 18 | Oct 31 | 196 |
| Ravensdale | — | Palmer 3 Ese | Apr 3 | Nov 11 | 219 |
| Ridgefield * | Warren, Scappoose, North Plains, Columbia, Deer Island | Scappoose Ind Ap | Apr 10 | Nov 2 | 209 |
| Rochester | Centralia, Fords Prairie, Onalaska, Tenino, Bucoda | Centralia | Apr 22 | Oct 27 | 188 |
| Shelton | — | Shelton Sanderson Fld | Apr 27 | Oct 16 | 175 |
| Skamokawa Valley | Rosburg, Grays River | Grays Rvr Hatchery | Apr 27 | Oct 22 | 178 |
| Skokomish | Grapeview, Union, Hoodsport | Cushman Powerhouse #2 | Mar 24 | Nov 15 | 235 |
| Snoqualmie | Fall | Snoqualmie Falls | Mar 30 | Nov 7 | 223 |
| Startup | — | Startup 1 E | Apr 15 | Oct 25 | 192 |
| Sunday Lake | Oso | Arlington | Apr 22 | Oct 19 | 181 |
| Tacoma | Federal Way, Lakewood, Parkland, Waller, McChord AFB, Fife, +3 more | Tacoma #1 | Mar 8 | Nov 14 | 250 |
| Tacoma | Longbranch, Lakewood, Key Center, Fort Lewis, University Place, Maplewood, +5 more | Tacoma Narrows Ap | Mar 11 | Nov 21 | 254 |
| Upper Elochoman | Clatskanie | Clatskanie | Apr 24 | Oct 24 | 184 |
| Vancouver | — | Portland Intl Ap | Mar 13 | Nov 19 | 247 |
| Vancouver | — | Vancouver Pearson Ap | Mar 29 | Nov 9 | 223 |
| Vancouver | Mount Vista, Hazel Dell, Felida, Lake Shore | Vancouver 4 Nne | Apr 26 | Oct 18 | 177 |
| Washougal | Fern Prairie | Skamania Fish Hatchery | Apr 29 | Oct 22 | 177 |
| Willapa | — | Raymond 2 S | Apr 26 | Oct 17 | 177 |
* Ridgefield 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 (Ridgefield, representative)
Computed from Ridgefield's average frost dates — the median-season location in this Washingtonzone 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 13 – Feb 27 | Apr 17 – Apr 24 | Jun 16 – Jul 6 | — | matures comfortably |
| Pepper | Very tender | Jan 30 – Feb 13 | Apr 24 – May 1 | Jun 23 – Jul 23 | — | matures comfortably |
| Cucumber | Tender | Mar 13 – Mar 20 | Apr 17 – Apr 24 | Jun 6 – Jun 26 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 17 – Apr 24 | Jun 1 – Jun 16 | — | matures comfortably |
| Bush bean | Tender | — | Apr 17 – Apr 24 | Jun 6 – Jun 16 | Sep 3 – Sep 13 | matures comfortably |
| Sweet corn | Tender | — | Apr 10 – Apr 24 | Jun 9 – Jul 9 | — | matures comfortably |
| Basil | Very tender | Feb 27 – Mar 13 | Apr 17 – Apr 24 | May 17 – Jun 1 | — | matures comfortably |
| Lettuce | Half-hardy | Feb 27 – Mar 13 | Mar 13 – Mar 27 | Apr 27 – May 12 | Aug 20 – Sep 4 | matures comfortably |
| Pea | Hardy | — | Feb 27 – Mar 13 | Apr 23 – May 8 | Aug 10 – Aug 25 | matures comfortably |
| Spinach | Hardy | — | Feb 27 – Mar 13 | Apr 8 – Apr 18 | Aug 30 – Sep 9 | matures comfortably |
| Carrot | Half-hardy | — | Mar 20 – Mar 27 | May 19 – Jun 8 | Jul 31 – Aug 20 | matures comfortably |
| Broccoli | Half-hardy | Feb 13 – Feb 27 | Mar 13 – Mar 27 | May 7 – May 27 | Aug 5 – Aug 25 | matures comfortably |
Which crops fit this growing season
Using Ridgefield's own 209-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 (Ridgefield)
From NOAA's 1991–2020 Climate Normals at station USW00004201. 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 | Apr 30 | May 17 | Oct 16 | Nov 3 | 169 |
| 32°F (freeze) | Apr 10 | May 1 | Nov 2 | Nov 23 | 209 |
| 28°F | Mar 3 | Mar 28 | Nov 19 | Dec 15 | 259 |
| 24°F | Feb 2 | Feb 28 | Dec 7 | Jan 16 | 313 |
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 53 locations is 1,765; Ridgefield's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,345 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,956 | cool-season crops (brassicas, greens) |
Hardiness zone 8b in Washington
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. Washington spans 8 hardiness zones in this dataset — see all Washington locations for the full range, including zones6a, 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 Washington?
- Zone 8b means an average annual extreme minimum winter temperature of 15 to 20 °F — the standard USDA measure of which perennials survive winter. 53 locations in Washington fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Washington's zone 8b is the growing season longest?
- Friday Harbor runs the longest season on this page at about 276 days; Eatonville is shortest at about 134 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 Washington's zone 8b?
- Using Ridgefield's frost dates (this page's median-season location): start seeds indoors about Feb 13 – Feb 27, then transplant outside about Apr 17 – Apr 24. 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 Washington'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 53 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.