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

Planting zone for 98582 — Salkum, WA

ZIP code 98582 (Salkum, Lewis County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 7 and the first fall frost November 13.

Where ZIP 98582 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 7

First frostNov 13

2012 zone8a

Was 8a on the 2012 map — half a zone warmer now. 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 Salkum, 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 Salkum, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 7median — 50% chance of a later frost

Safe for tender plantsMay 8only 10% chance of frost after

First fall frostNovember 13median — 10% chance by Oct 24

Growing season215 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 6 and returns around December 1.

From the NOAA station Mayfield Pwr Plt, WA — 2 miles away, elevation 279 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 98582

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 24 – Mar 10

SpinachSow outdoors · Feb 24 – Mar 17

Broccoli, cabbageStart indoors · Jan 27 – Feb 10

Broccoli, cabbageTransplant · Mar 17 – Mar 31

Onion setsPlant outdoors · Mar 10 – Mar 24

PotatoesPlant outdoors · Mar 17 – Mar 31

LettuceSow outdoors · Mar 10 – Mar 24

Carrots, beetsSow outdoors · Mar 17 – Mar 31

TomatoesStart indoors · Feb 10 – Feb 24

TomatoesTransplant · Apr 14 – Apr 28

Peppers, eggplantStart indoors · Jan 27 – Feb 10

Peppers, eggplantTransplant · Apr 21 – May 5

BeansSow outdoors · Apr 14 – Apr 28

Sweet cornSow outdoors · Apr 14 – Apr 28

Cucumbers, squashSow outdoors · Apr 14 – Apr 28

Fall lettuce, spinachSow outdoors · Sep 18 – Oct 2

GarlicPlant cloves · Oct 30 – Dec 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Nov 13) 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 98582 came on Feb 28 — about the same time as the 1991–2020 average (Feb 28).

average
Feb 282026
Feb 28

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 Salkum, WA.

Soil in Salkum, WA

The soil mapped at the center of ZIP 98582 is Newaukum — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables

pH6.1slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter10%high

Hydrologic groupBwater soaks in moderately

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Newaukum gravelly silt loam, 5 to 15 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 98582; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Salkum, WA

Summer high81 °Faverage high, July

Winter low33 °Faverage low, January

Hot days24days a year at 90 °F or more

Freezing nights66nights a year at 32 °F or less

Growing degree days2,054base 50 °F — the season’s usable heat

Longest day15 h 50 mindaylight on June 21

Shortest day8 h 34 mindaylight on December 21

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

Precipitation58.7 inper year, rain and melted snow

Snowfall3 inper year; 2 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: Mayfield Pwr Plt, WA (2 mi away); precipitation: Mayfield Pwr Plt, WA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Silver Creek, WA · 9 mi

985648a

Mossyrock, WA · 11 mi

Silverlake, WA · 15 mi

Washington planting zones →

Questions about 98582

What planting zone is ZIP code 98582?

ZIP code 98582 (Salkum, 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 Salkum, WA?

The median last spring frost (32 °F) near 98582 is April 7; after May 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mayfield Pwr Plt station.

When is the first frost in Salkum, WA?

The median first fall frost near 98582 is November 13, giving a median frost-free growing season of 215 days.

When should I plant tomatoes in 98582?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 98582 get?

About 58.7 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Mayfield Pwr Plt station).

How hot do summers get in Salkum, WA?

The average high peaks at 81 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 98582 have?

The USDA soil survey maps Newaukum at the center of ZIP 98582: gravelly silt loam, well drained, pH about 6.1 (slightly acidic).

Did spring come early in Salkum, WA in 2026?

Spring leaf-out near 98582 came on Feb 28 in 2026, about the same as the 1991–2020 average (Feb 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Salkum, WA?

Long-day onions: the longest day near 98582 is 15 h 50 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 98582 change?

Yes. The 2012 USDA map put 98582 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.