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

Planting zone for 99040 — Wellpinit, WA

ZIP code 99040 (Wellpinit, Stevens County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is June 6 and the first fall frost September 11.

Where ZIP 99040 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostJun 6

First frostSep 11

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Wellpinit, 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 Wellpinit, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 6median — 50% chance of a later frost

Safe for tender plantsJuly 5only 10% chance of frost after

First fall frostSeptember 11median — 10% chance by Aug 26

Growing season94 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 11 and returns around September 27.

From the NOAA station Davenport, WA — 18 miles away, elevation 2,369 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 99040

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 25 – May 9

SpinachSow outdoors · Apr 25 – May 16

Broccoli, cabbageStart indoors · Mar 28 – Apr 11

Broccoli, cabbageTransplant · May 16 – May 30

Onion setsPlant outdoors · May 9 – May 23

PotatoesPlant outdoors · May 16 – May 30

LettuceSow outdoors · May 9 – May 23

Carrots, beetsSow outdoors · May 16 – May 30

TomatoesStart indoors · Apr 11 – Apr 25

TomatoesTransplant · Jun 13 – Jun 27

Peppers, eggplantStart indoors · Mar 28 – Apr 11

Peppers, eggplantTransplant · Jun 20 – Jul 4

BeansSow outdoors · Jun 13 – Jun 27

Sweet cornSow outdoors · Jun 13 – Jun 27

Cucumbers, squashSow outdoors · Jun 13 – Jun 27

Fall lettuce, spinachSow outdoors · Jul 17 – Jul 31

GarlicPlant cloves · Aug 28 – Oct 2

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 6) and first fall frost (Sep 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 99040 came on Apr 2 — 6 days earlier than the 1991–2020 average (Apr 8).

average
Apr 82026
Apr 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 7a in Washington

590 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Wellpinit, WA.

Soil in Wellpinit, WA

The soil mapped at the center of ZIP 99040 is Moscow — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter75%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Moscow ashy silt loam, 25 to 40 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 99040; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Wellpinit, WA

Summer high83 °Faverage high, August

Winter low19 °Faverage low, January

Hot days18days a year at 90 °F or more

Freezing nights175nights a year at 32 °F or less

Growing degree days1,574base 50 °F — the season’s usable heat

Longest day16 h 02 mindaylight on June 21

Shortest day8 h 23 mindaylight on December 21

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

Precipitation14 inper year, rain and melted snow

Snowfall30 inper year; 48 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: Davenport, WA (18 mi away); precipitation: Davenport, WA (18 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

990136b

Ford, WA · 8 mi

991297a

Fruitland, WA · 10 mi

990346b

Tumtum, WA · 11 mi

991736b

Springdale, WA · 12 mi

990296b

Reardan, WA · 16 mi

991226b

Davenport, WA · 17 mi

Washington planting zones →

Questions about 99040

What planting zone is ZIP code 99040?

ZIP code 99040 (Wellpinit, WA) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Wellpinit, WA?

The median last spring frost (32 °F) near 99040 is June 6; after July 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Davenport station.

When is the first frost in Wellpinit, WA?

The median first fall frost near 99040 is September 11, giving a median frost-free growing season of 94 days.

When should I plant tomatoes in 99040?

Start tomato seeds indoors around Apr 11 – Apr 25 and set transplants outside around Jun 13 – Jun 27, one to three weeks after the median last frost.

How much rain and snow does 99040 get?

About 14 inches of precipitation a year and 30 inches of snowfall (NOAA 1991–2020 normals, Davenport station).

How hot do summers get in Wellpinit, WA?

The average high peaks at 83 °F in August, with about 18 days a year at 90 °F or more.

What kind of soil does 99040 have?

The USDA soil survey maps Moscow at the center of ZIP 99040: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Wellpinit, WA in 2026?

Spring leaf-out near 99040 came on Apr 2 in 2026, 6 days earlier than the 1991–2020 average (Apr 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Wellpinit, WA?

Long-day onions: the longest day near 99040 is 16 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99040 change?

Yes. The 2012 USDA map put 99040 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.