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

Planting zone for 99185 — Wilbur, WA

ZIP code 99185 (Wilbur, Lincoln County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is June 1 and the first fall frost September 22.

Where ZIP 99185 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostJun 1

First frostSep 22

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Wilbur, 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 Wilbur, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 1median — 50% chance of a later frost

Safe for tender plantsJune 22only 10% chance of frost after

First fall frostSeptember 22median — 10% chance by Sep 2

Growing season112 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around October 3.

From the NOAA station Wilbur, WA — 3 miles away, elevation 2,264 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 99185

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

Fall lettuce, spinachSow outdoors · Jul 28 – Aug 11

GarlicPlant cloves · Sep 8 – Oct 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 22) 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 99185 came on Apr 1 — 8 days earlier than the 1991–2020 average (Apr 9).

average
Apr 92026
Apr 1

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 6b in Washington

581 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Wilbur, WA.

Soil in Wilbur, WA

The soil mapped at the center of ZIP 99185 is Bagdad — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupBwater soaks in moderately

Farmland classprime farmlandUSDA classification

Map unit: Bagdad silt loam, 0 to 7 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 99185; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Wilbur, WA

Summer high85 °Faverage high, July

Winter low20 °Faverage low, January

Hot days25days a year at 90 °F or more

Freezing nights174nights a year at 32 °F or less

Growing degree days1,813base 50 °F — the season’s usable heat

Longest day16 h 00 mindaylight on June 21

Shortest day8 h 24 mindaylight on December 21

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

Precipitation12.5 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wilbur, WA (3 mi away); precipitation: Wilbur, WA (3 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.

Electric City, WA · 19 mi

991247b

Elmer City, WA · 22 mi

991167a

Coulee Dam, WA · 22 mi

991226b

Davenport, WA · 24 mi

Washington planting zones →

Questions about 99185

What planting zone is ZIP code 99185?

ZIP code 99185 (Wilbur, WA) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Wilbur, WA?

The median last spring frost (32 °F) near 99185 is June 1; after June 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wilbur station.

When is the first frost in Wilbur, WA?

The median first fall frost near 99185 is September 22, giving a median frost-free growing season of 112 days.

When should I plant tomatoes in 99185?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 99185 get?

About 12.5 inches of precipitation a year (NOAA 1991–2020 normals, Wilbur station).

How hot do summers get in Wilbur, WA?

The average high peaks at 85 °F in July, with about 25 days a year at 90 °F or more.

What kind of soil does 99185 have?

The USDA soil survey maps Bagdad at the center of ZIP 99185: silt loam, well drained, pH about 6.7 (neutral).

Did spring come early in Wilbur, WA in 2026?

Spring leaf-out near 99185 came on Apr 1 in 2026, 8 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Wilbur, WA?

Long-day onions: the longest day near 99185 is 16 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99185 change?

Yes. The 2012 USDA map put 99185 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.