Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for Oak Harbor, WA

Oak Harbor, WA is in USDA zone 8b across its 2 ZIP codes. The median last spring frost is March 13 and the first fall frost November 14.

Oak Harbor on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone8b15 to 20 °F
ZIP codes2
Last frostMar 13
First frostNov 14
Growing season244 days

8b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Oak Harbor, WA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Oak Harbor, WA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 13median — 50% chance of a later frost
Safe for tender plantsApril 1only 10% chance of frost after
First fall frostNovember 14median — 10% chance by Oct 26
Growing season244 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 18 and returns around December 1.

From the NOAA station Whidbey Island NAS, WA, elevation 46 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Oak Harbor

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 30 – Feb 13
SpinachSow outdoors · Jan 30 – Feb 20
Broccoli, cabbageStart indoors · Jan 2 – Jan 16
Broccoli, cabbageTransplant · Feb 20 – Mar 6
Onion setsPlant outdoors · Feb 13 – Feb 27
PotatoesPlant outdoors · Feb 20 – Mar 6
LettuceSow outdoors · Feb 13 – Feb 27
Carrots, beetsSow outdoors · Feb 20 – Mar 6
TomatoesStart indoors · Jan 16 – Jan 30
TomatoesTransplant · Mar 20 – Apr 3
Peppers, eggplantStart indoors · Jan 2 – Jan 16
Peppers, eggplantTransplant · Mar 27 – Apr 10
BeansSow outdoors · Mar 20 – Apr 3
Sweet cornSow outdoors · Mar 20 – Apr 3
Cucumbers, squashSow outdoors · Mar 20 – Apr 3
Fall lettuce, spinachSow outdoors · Sep 19 – Oct 3
GarlicPlant cloves · Oct 31 – Dec 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 13) and first fall frost (Nov 14) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 98278 came on Feb 15 — about the same time as the 1991–2020 average (Feb 16).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 8b in Washington

614 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. Each links to its USDA PLANTS profile.

Trees 32

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fbigleaf maple60 ft · blooms mid spring · medium shade tolerance · to −14 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °F

Shrubs 114

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FBarclay's willow15 ft · high shade tolerance · to −43 °F

Wildflowers & perennials 293

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 157

Alaska brome5 ft · blooms late spring · low shade tolerance · to −18 °FAlaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °F

Vines 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Oak Harbor, WA.

Soil in Oak Harbor, WA

The soil mapped at the center of ZIP 98278 is Coveland — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables
pH6.4slightly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter9%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Coveland loam, cool, 0 to 5 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 98278; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oak Harbor, WA

Summer high70 °Faverage high, August
Winter low37 °Faverage low, February
Hot days0days a year at 90 °F or more
Freezing nights40nights a year at 32 °F or less
Growing degree days1,664base 50 °F — the season’s usable heat
Longest day16 h 06 mindaylight on June 21
Shortest day8 h 19 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation19.9 inper year, rain and melted snow
Snowfall5 inper year; 3 days with snow on the ground

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 49 °F, low 38 °F 49°38° JanFebruary: average high 51 °F, low 37 °F 51°37° FebMarch: average high 55 °F, low 40 °F 55°40° MarApril: average high 58 °F, low 43 °F 58°43° AprMay: average high 62 °F, low 48 °F 62°48° MayJune: average high 66 °F, low 52 °F 66°52° JunJuly: average high 69 °F, low 54 °F 69°54° JulAugust: average high 70 °F, low 54 °F 70°54° AugSeptember: average high 67 °F, low 50 °F 67°50° SepOctober: average high 60 °F, low 46 °F 60°46° OctNovember: average high 54 °F, low 41 °F 54°41° NovDecember: average high 49 °F, low 38 °F 49°38° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 2.43 in precipitation, 1.1 in snowfall 2.4❄1 JanFebruary: 1.63 in precipitation, 1 in snowfall 1.6❄1 FebMarch: 1.68 in precipitation, 0.6 in snowfall 1.7❄1 MarApril: 1.69 in precipitation 1.7 AprMay: 1.69 in precipitation 1.7 MayJune: 1.12 in precipitation 1.1 JunJuly: 0.63 in precipitation 0.6 JulAugust: 0.85 in precipitation 0.8 AugSeptember: 1.08 in precipitation 1.1 SepOctober: 2.04 in precipitation 2.0 OctNovember: 3.13 in precipitation, 0.3 in snowfall 3.1 NovDecember: 1.95 in precipitation, 2.4 in snowfall 1.9❄2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Whidbey Island NAS, WA (within 1 mile); precipitation: Whidbey Island NAS, WA (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Oak Harbor

982778b
15 to 20 °F
982788b
15 to 20 °F

Washington planting zones →

Questions about Oak Harbor

What planting zone is Oak Harbor, WA?

Oak Harbor, WA is in USDA hardiness zone 8b on the 2023 map (8b: 15 to 20 °F).

When is the last frost in Oak Harbor, WA?

The median last spring frost is March 13 and the median first fall frost is November 14 (NOAA 1991–2020 normals, Whidbey Island NAS station).

When can I plant a garden in Oak Harbor, WA?

Cool-season crops like peas and spinach go in around Jan 30 – Feb 20; tomatoes, peppers, beans and squash after about Mar 20, once frost risk has passed.

What kind of onions grow in Oak Harbor, WA?

Long-day onions: the longest day is 16 h 06 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Oak Harbor, WA get?

About 19.9 inches of precipitation a year and 5 inches of snowfall (NOAA 1991–2020 normals).