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

Planting zone for 99323 — Burbank, WA

ZIP code 99323 (Burbank, Walla Walla County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 7 and the first fall frost October 22.

Where ZIP 99323 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 frostApr 7
First frostOct 22
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 Burbank, 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 Burbank, 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 plantsApril 30only 10% chance of frost after
First fall frostOctober 22median — 10% chance by Oct 6
Growing season199 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 18 and returns around November 4.

From the NOAA station Ice Harbor Dam, WA — 4 miles away, elevation 367 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 99323

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 · Aug 27 – Sep 10
GarlicPlant cloves · Oct 8 – Nov 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Oct 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 99323 came on Mar 5 — 3 days earlier than the 1991–2020 average (Mar 8).

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.

Trees 31

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fbigleaf maple60 ft · blooms mid spring · medium shade tolerance · to −14 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °F

Shrubs 105

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FBarclay's willow15 ft · high shade tolerance · to −43 °F

Wildflowers & perennials 282

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 157

Alaska brome5 ft · blooms late spring · low shade tolerance · to −18 °FAlaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °F

Vines 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

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 Burbank, WA.

Soil in Burbank, WA

The soil mapped at the center of ZIP 99323 is Quincy — loamy fine sand, excessively drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding
pH7.3neutral; most vegetables like 6.0–7.0
DrainageExcessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Quincy loamy fine sand, 8 to 15 percent slopes, eroded.

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 99323; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Burbank, WA

Summer high89 °Faverage high, July
Winter low29 °Faverage low, January
Hot days37days a year at 90 °F or more
Freezing nights84nights a year at 32 °F or less
Growing degree days3,172base 50 °F — the season’s usable heat
Longest day15 h 47 mindaylight on June 21
Shortest day8 h 37 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation11.1 inper year, rain and melted snow
Snowfall2 inper year; 2 days with snow on the ground

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 42 °F, low 29 °F 42°29° JanFebruary: average high 48 °F, low 30 °F 48°30° FebMarch: average high 58 °F, low 35 °F 58°35° MarApril: average high 65 °F, low 41 °F 65°41° AprMay: average high 74 °F, low 48 °F 74°48° MayJune: average high 80 °F, low 54 °F 80°54° JunJuly: average high 89 °F, low 61 °F 89°61° JulAugust: average high 89 °F, low 59 °F 89°59° AugSeptember: average high 80 °F, low 51 °F 80°51° SepOctober: average high 66 °F, low 42 °F 66°42° OctNovember: average high 51 °F, low 35 °F 51°35° NovDecember: average high 42 °F, low 29 °F 42°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 1.42 in precipitation, 0.2 in snowfall 1.4 JanFebruary: 1.04 in precipitation, 0.2 in snowfall 1.0 FebMarch: 1.02 in precipitation, 0.1 in snowfall 1.0 MarApril: 0.98 in precipitation 1.0 AprMay: 1.15 in precipitation 1.1 MayJune: 0.85 in precipitation 0.8 JunJuly: 0.26 in precipitation 0.3 JulAugust: 0.30 in precipitation 0.3 AugSeptember: 0.39 in precipitation 0.4 SepOctober: 1.02 in precipitation 1.0 OctNovember: 1.26 in precipitation, 0.1 in snowfall 1.3 NovDecember: 1.43 in precipitation, 1.4 in snowfall 1.4❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ice Harbor Dam, WA (4 mi away); precipitation: Ice Harbor Dam, WA (4 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.

993637b
Wallula, WA · 10 mi
993027b
Pasco, WA · 11 mi
993607a
Touchet, WA · 12 mi
993017a
Pasco, WA · 14 mi
993377b
Kennewick, WA · 14 mi
993367b
Kennewick, WA · 15 mi
978357a
Helix, OR · 21 mi
993307a
Eltopia, WA · 22 mi

Washington planting zones →

Questions about 99323

What planting zone is ZIP code 99323?

ZIP code 99323 (Burbank, 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 Burbank, WA?

The median last spring frost (32 °F) near 99323 is April 7; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ice Harbor Dam station.

When is the first frost in Burbank, WA?

The median first fall frost near 99323 is October 22, giving a median frost-free growing season of 199 days.

When should I plant tomatoes in 99323?

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 99323 get?

About 11.1 inches of precipitation a year and 2 inches of snowfall (NOAA 1991–2020 normals, Ice Harbor Dam station).

How hot do summers get in Burbank, WA?

The average high peaks at 89 °F in July, with about 37 days a year at 90 °F or more.

What kind of soil does 99323 have?

The USDA soil survey maps Quincy at the center of ZIP 99323: loamy fine sand, excessively drained, pH about 7.3 (neutral).

Did spring come early in Burbank, WA in 2026?

Spring leaf-out near 99323 came on Mar 5 in 2026, 3 days earlier than the 1991–2020 average (Mar 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Burbank, WA?

Long-day onions: the longest day near 99323 is 15 h 47 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).