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

Planting zone for Sumner, WA

Sumner, WA is in USDA zone 8b across its 2 ZIP codes. The median last spring frost is April 11 and the first fall frost October 30.

Sumner on the zone map

Outlined: its 1 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 frostApr 11

First frostOct 30

Growing season202 days

8b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Sumner, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 11median — 50% chance of a later frost

Safe for tender plantsApril 29only 10% chance of frost after

First fall frostOctober 30median — 10% chance by Oct 13

Growing season202 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 16 and returns around November 14.

From the NOAA station Mcmillin Rsvr, WA, elevation 581 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 Sumner

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 28 – Mar 14

SpinachSow outdoors · Feb 28 – Mar 21

Broccoli, cabbageStart indoors · Jan 31 – Feb 14

Broccoli, cabbageTransplant · Mar 21 – Apr 4

Onion setsPlant outdoors · Mar 14 – Mar 28

PotatoesPlant outdoors · Mar 21 – Apr 4

LettuceSow outdoors · Mar 14 – Mar 28

Carrots, beetsSow outdoors · Mar 21 – Apr 4

TomatoesStart indoors · Feb 14 – Feb 28

TomatoesTransplant · Apr 18 – May 2

Peppers, eggplantStart indoors · Jan 31 – Feb 14

Peppers, eggplantTransplant · Apr 25 – May 9

BeansSow outdoors · Apr 18 – May 2

Sweet cornSow outdoors · Apr 18 – May 2

Cucumbers, squashSow outdoors · Apr 18 – May 2

Fall lettuce, spinachSow outdoors · Sep 4 – Sep 18

GarlicPlant cloves · Oct 16 – Nov 20

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 30) 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 98390 came on Feb 17 — about the same time as the 1991–2020 average (Feb 19).

average
Feb 192026
Feb 17

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 Sumner, WA.

Soil in Sumner, WA

The soil mapped at the center of ZIP 98390 is Briscot — loam, poorly drained.

TextureLoama good balance for most vegetables

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

DrainagePoorly drainedconsider raised beds

Organic matter6%high

Hydrologic groupB/Dmoderate when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Briscot loam.

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 98390; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sumner, WA

Summer high77 °Faverage high, August

Winter low33 °Faverage low, January

Hot days3days a year at 90 °F or more

Freezing nights60nights a year at 32 °F or less

Growing degree days1,715base 50 °F — the season’s usable heat

Longest day15 h 55 mindaylight on June 21

Shortest day8 h 29 mindaylight on December 21

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

Precipitation45.1 inper year, rain and melted snow

Snowfall6 inper year; 5 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: Mcmillin Rsvr, WA (6 mi away); precipitation: Mcmillin Rsvr, WA (6 mi away). Daylight is calculated from latitude.

ZIP codes in Sumner

Washington planting zones →

Questions about Sumner

What planting zone is Sumner, WA?

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

When is the last frost in Sumner, WA?

The median last spring frost is April 11 and the median first fall frost is October 30 (NOAA 1991–2020 normals, Mcmillin Rsvr station).

When can I plant a garden in Sumner, WA?

Cool-season crops like peas and spinach go in around Feb 28 – Mar 21; tomatoes, peppers, beans and squash after about Apr 18, once frost risk has passed.

What kind of onions grow in Sumner, WA?

Long-day onions: the longest day is 15 h 55 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Sumner, WA get?

About 45.1 inches of precipitation a year and 6 inches of snowfall (NOAA 1991–2020 normals).