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

Planting zone for 99360 — Touchet, WA

ZIP code 99360 (Touchet, Walla Walla County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 2 and the first fall frost October 1.

Where ZIP 99360 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 frostMay 2

First frostOct 1

2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Touchet, 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 Touchet, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 2median — 50% chance of a later frost

Safe for tender plantsMay 18only 10% chance of frost after

First fall frostOctober 1median — 10% chance by Sep 14

Growing season151 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 12.

From the NOAA station Whitman Mission, WA — 11 miles away, elevation 633 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 99360

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 21 – Apr 4

SpinachSow outdoors · Mar 21 – Apr 11

Broccoli, cabbageStart indoors · Feb 21 – Mar 7

Broccoli, cabbageTransplant · Apr 11 – Apr 25

Onion setsPlant outdoors · Apr 4 – Apr 18

PotatoesPlant outdoors · Apr 11 – Apr 25

LettuceSow outdoors · Apr 4 – Apr 18

Carrots, beetsSow outdoors · Apr 11 – Apr 25

TomatoesStart indoors · Mar 7 – Mar 21

TomatoesTransplant · May 9 – May 23

Peppers, eggplantStart indoors · Feb 21 – Mar 7

Peppers, eggplantTransplant · May 16 – May 30

BeansSow outdoors · May 9 – May 23

Sweet cornSow outdoors · May 9 – May 23

Cucumbers, squashSow outdoors · May 9 – May 23

Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20

GarlicPlant cloves · Sep 17 – Oct 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 1) 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 99360 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 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 Touchet, WA.

Soil in Touchet, WA

The soil mapped at the center of ZIP 99360 is Lickskillet — very cobbly silt loam, well drained.

TextureVery cobbly silt loama good balance for most vegetables

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Basalt rockland, steep.

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 99360; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Touchet, WA

Summer high90 °Faverage high, July

Winter low27 °Faverage low, January

Hot days44days a year at 90 °F or more

Freezing nights125nights a year at 32 °F or less

Growing degree days2,616base 50 °F — the season’s usable heat

Longest day15 h 46 mindaylight on June 21

Shortest day8 h 38 mindaylight on December 21

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

Precipitation15.4 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: Whitman Mission, WA (11 mi away); precipitation: Whitman Mission, WA (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

College Place, WA · 14 mi

978357a

Helix, OR · 14 mi

993627a

Walla Walla, WA · 17 mi

978137a

Athena, OR · 18 mi

978627a

Milton Freewater, OR · 20 mi

993017a

Pasco, WA · 24 mi

Washington planting zones →

Questions about 99360

What planting zone is ZIP code 99360?

ZIP code 99360 (Touchet, 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 Touchet, WA?

The median last spring frost (32 °F) near 99360 is May 2; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Whitman Mission station.

When is the first frost in Touchet, WA?

The median first fall frost near 99360 is October 1, giving a median frost-free growing season of 151 days.

When should I plant tomatoes in 99360?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 99360 get?

About 15.4 inches of precipitation a year (NOAA 1991–2020 normals, Whitman Mission station).

How hot do summers get in Touchet, WA?

The average high peaks at 90 °F in July, with about 44 days a year at 90 °F or more.

What kind of soil does 99360 have?

The USDA soil survey maps Lickskillet at the center of ZIP 99360: very cobbly silt loam, well drained, pH about 6.7 (neutral).

Did spring come early in Touchet, WA in 2026?

Spring leaf-out near 99360 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 Touchet, WA?

Long-day onions: the longest day near 99360 is 15 h 46 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).