Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 98239 — Coupeville, WA

ZIP code 98239 (Coupeville, Island County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 17 and the first fall frost November 11.

Where ZIP 98239 is

Outlined: the ZIP code area · 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

Coldest night−9.4 to −6.7 °C

Last frostMar 17

First frostNov 11

2012 zone8b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Coupeville, 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 Coupeville, WA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMarch 17median — 50% chance of a later frost

Safe for tender plantsApril 3only 10% chance of frost after

First fall frostNovember 11median — 10% chance by Oct 21

Growing season237 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 21 and returns around November 28.

From the NOAA station Coupeville 1 S, WA — 2 miles away, elevation 49 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 98239

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 3 – Feb 17

SpinachSow outdoors · Feb 3 – Feb 24

Broccoli, cabbageStart indoors · Jan 6 – Jan 20

Broccoli, cabbageTransplant · Feb 24 – Mar 10

Onion setsPlant outdoors · Feb 17 – Mar 3

PotatoesPlant outdoors · Feb 24 – Mar 10

LettuceSow outdoors · Feb 17 – Mar 3

Carrots, beetsSow outdoors · Feb 24 – Mar 10

TomatoesStart indoors · Jan 20 – Feb 3

TomatoesTransplant · Mar 24 – Apr 7

Peppers, eggplantStart indoors · Jan 6 – Jan 20

Peppers, eggplantTransplant · Mar 31 – Apr 14

BeansSow outdoors · Mar 24 – Apr 7

Sweet cornSow outdoors · Mar 24 – Apr 7

Cucumbers, squashSow outdoors · Mar 24 – Apr 7

Fall lettuce, spinachSow outdoors · Sep 16 – Sep 30

GarlicPlant cloves · Oct 28 – Dec 2

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 17) and first fall frost (Nov 11) 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 98239 came on Feb 16 — 4 days earlier than the 1991–2020 average (Feb 20).

average
Feb 202026
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.

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 Coupeville, WA.

Soil in Coupeville, WA

The soil mapped at the center of ZIP 98239 is Keystone — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.5moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter75%high

Hydrologic groupAwater soaks in fast

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Keystone-Utsalady complex, 0 to 3 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 98239; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Coupeville, WA

Summer high71 °Faverage high, August

Winter low36 °Faverage low, February

Hot days1days a year at 90 °F or more

Freezing nights32nights a year at 32 °F or less

Growing degree days1,420base 50 °F — the season’s usable heat

Longest day16 h 05 mindaylight on June 21

Shortest day8 h 20 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation21.7 inper year, rain and melted snow

Snowfall3 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Coupeville 1 S, WA (2 mi away); precipitation: Coupeville 1 S, WA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

982828b

Camano Island, WA · 7 mi

982778b

Oak Harbor, WA · 9 mi

982538b

Greenbank, WA · 9 mi

982788b

Oak Harbor, WA · 10 mi

983589a

Nordland, WA · 11 mi

983398b

Port Hadlock, WA · 13 mi

983688b

Port Townsend, WA · 13 mi

982498b

Freeland, WA · 14 mi

Washington planting zones →

Questions about 98239

What planting zone is ZIP code 98239?

ZIP code 98239 (Coupeville, WA) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Coupeville, WA?

The median last spring frost (32 °F) near 98239 is March 17; after April 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Coupeville 1 S station.

When is the first frost in Coupeville, WA?

The median first fall frost near 98239 is November 11, giving a median frost-free growing season of 237 days.

When should I plant tomatoes in 98239?

Start tomato seeds indoors around Jan 20 – Feb 3 and set transplants outside around Mar 24 – Apr 7, one to three weeks after the median last frost.

How much rain and snow does 98239 get?

About 21.7 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Coupeville 1 S station).

How hot do summers get in Coupeville, WA?

The average high peaks at 71 °F in August, with about 1 days a year at 90 °F or more.

What kind of soil does 98239 have?

The USDA soil survey maps Keystone at the center of ZIP 98239: slightly decomposed plant material, somewhat excessively drained, pH about 5.5 (moderately acidic).

Did spring come early in Coupeville, WA in 2026?

Spring leaf-out near 98239 came on Feb 16 in 2026, 4 days earlier than the 1991–2020 average (Feb 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Coupeville, WA?

Long-day onions: the longest day near 98239 is 16 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).