Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 98223 — Arlington, WA

ZIP code 98223 (Arlington, Snohomish County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 22 and the first fall frost October 19.

Where ZIP 98223 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 frostApr 22

First frostOct 19

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 Arlington, 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 Arlington, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 22median — 50% chance of a later frost

Safe for tender plantsMay 6only 10% chance of frost after

First fall frostOctober 19median — 10% chance by Oct 3

Growing season181 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 25 and returns around November 3.

From the NOAA station Arlington, WA — 8 miles away, elevation 102 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 98223

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 11 – Mar 25

SpinachSow outdoors · Mar 11 – Apr 1

Broccoli, cabbageStart indoors · Feb 11 – Feb 25

Broccoli, cabbageTransplant · Apr 1 – Apr 15

Onion setsPlant outdoors · Mar 25 – Apr 8

PotatoesPlant outdoors · Apr 1 – Apr 15

LettuceSow outdoors · Mar 25 – Apr 8

Carrots, beetsSow outdoors · Apr 1 – Apr 15

TomatoesStart indoors · Feb 25 – Mar 11

TomatoesTransplant · Apr 29 – May 13

Peppers, eggplantStart indoors · Feb 11 – Feb 25

Peppers, eggplantTransplant · May 6 – May 20

BeansSow outdoors · Apr 29 – May 13

Sweet cornSow outdoors · Apr 29 – May 13

Cucumbers, squashSow outdoors · Apr 29 – May 13

Fall lettuce, spinachSow outdoors · Aug 24 – Sep 7

GarlicPlant cloves · Oct 5 – Nov 9

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 22) and first fall frost (Oct 19) 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 98223 came on Mar 2 — 5 days earlier than the 1991–2020 average (Mar 7).

average
Mar 72026
Mar 2

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 Arlington, WA.

Soil in Arlington, WA

The soil mapped at the center of ZIP 98223 is Tokul — gravelly medial loam, moderately well drained.

TextureGravelly medial loama good balance for most vegetables

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter12.5%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Tokul-Winston gravelly loams, 25 to 65 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 98223; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Arlington, WA

Summer high78 °Faverage high, August

Winter low28 °Faverage low, February

Hot days5days a year at 90 °F or more

Freezing nights94nights a year at 32 °F or less

Growing degree days1,458base 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)

Precipitation49 inper year, rain and melted snow

Snowfall4 inper year; 3 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Arlington, WA (8 mi away); precipitation: Arlington, WA (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

982598a

North Lakewood, WA · 13 mi

982748b

Mount Vernon, WA · 13 mi

982588b

Lake Stevens, WA · 14 mi

982708b

Marysville, WA · 14 mi

982528a

Granite Falls, WA · 15 mi

982718b

Marysville, WA · 16 mi

982908b

Snohomish, WA · 18 mi

982018b

Everett, WA · 19 mi

Washington planting zones →

Questions about 98223

What planting zone is ZIP code 98223?

ZIP code 98223 (Arlington, 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 Arlington, WA?

The median last spring frost (32 °F) near 98223 is April 22; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Arlington station.

When is the first frost in Arlington, WA?

The median first fall frost near 98223 is October 19, giving a median frost-free growing season of 181 days.

When should I plant tomatoes in 98223?

Start tomato seeds indoors around Feb 25 – Mar 11 and set transplants outside around Apr 29 – May 13, one to three weeks after the median last frost.

How much rain and snow does 98223 get?

About 49 inches of precipitation a year and 4 inches of snowfall (NOAA 1991–2020 normals, Arlington station).

How hot do summers get in Arlington, WA?

The average high peaks at 78 °F in August, with about 5 days a year at 90 °F or more.

What kind of soil does 98223 have?

The USDA soil survey maps Tokul at the center of ZIP 98223: gravelly medial loam, moderately well drained, pH about 5.8 (moderately acidic).

Did spring come early in Arlington, WA in 2026?

Spring leaf-out near 98223 came on Mar 2 in 2026, 5 days earlier than the 1991–2020 average (Mar 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Arlington, WA?

Long-day onions: the longest day near 98223 is 16 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).