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

Planting zone for 99019 — Liberty Lake, WA

ZIP code 99019 (Liberty Lake, Spokane County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 26 and the first fall frost October 15.

Where ZIP 99019 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 frostApr 26
First frostOct 15
2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Liberty Lake, 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 Liberty Lake, WA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 26median — 50% chance of a later frost
Safe for tender plantsMay 10only 10% chance of frost after
First fall frostOctober 15median — 10% chance by Sep 30
Growing season170 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around October 27.

From the NOAA station Spokane Felts Field, WA — 12 miles away, elevation 1,952 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 99019

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 15 – Mar 29
SpinachSow outdoors · Mar 15 – Apr 5
Broccoli, cabbageStart indoors · Feb 15 – Mar 1
Broccoli, cabbageTransplant · Apr 5 – Apr 19
Onion setsPlant outdoors · Mar 29 – Apr 12
PotatoesPlant outdoors · Apr 5 – Apr 19
LettuceSow outdoors · Mar 29 – Apr 12
Carrots, beetsSow outdoors · Apr 5 – Apr 19
TomatoesStart indoors · Mar 1 – Mar 15
TomatoesTransplant · May 3 – May 17
Peppers, eggplantStart indoors · Feb 15 – Mar 1
Peppers, eggplantTransplant · May 10 – May 24
BeansSow outdoors · May 3 – May 17
Sweet cornSow outdoors · May 3 – May 17
Cucumbers, squashSow outdoors · May 3 – May 17
Fall lettuce, spinachSow outdoors · Aug 20 – Sep 3
GarlicPlant cloves · Oct 1 – Nov 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 26) and first fall frost (Oct 15) 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 99019 came on Apr 2 — 7 days earlier than the 1991–2020 average (Apr 9).

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.

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 102

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 279

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 154

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 Liberty Lake, WA.

Soil in Liberty Lake, WA

The soil mapped at the center of ZIP 99019 is Kellerbutte — 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 groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Kellerbutte-Brevco complex, 30 to 60 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 99019; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Liberty Lake, WA

Summer high87 °Faverage high, July
Winter low26 °Faverage low, January
Hot days29days a year at 90 °F or more
Freezing nights123nights a year at 32 °F or less
Growing degree days2,402base 50 °F — the season’s usable heat
Longest day15 h 59 mindaylight on June 21
Shortest day8 h 25 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation29.4 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 38 °F, low 26 °F 38°26° JanFebruary: average high 43 °F, low 27 °F 43°27° FebMarch: average high 51 °F, low 32 °F 51°32° MarApril: average high 60 °F, low 37 °F 60°37° AprMay: average high 70 °F, low 44 °F 70°44° MayJune: average high 76 °F, low 50 °F 76°50° JunJuly: average high 87 °F, low 56 °F 87°56° JulAugust: average high 86 °F, low 55 °F 86°55° AugSeptember: average high 76 °F, low 47 °F 76°47° SepOctober: average high 60 °F, low 38 °F 60°38° OctNovember: average high 45 °F, low 31 °F 45°31° NovDecember: average high 37 °F, low 26 °F 37°26° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.57 in precipitation 3.6 JanFebruary: 2.48 in precipitation 2.5 FebMarch: 2.93 in precipitation 2.9 MarApril: 2.10 in precipitation 2.1 AprMay: 2.33 in precipitation 2.3 MayJune: 1.89 in precipitation 1.9 JunJuly: 0.93 in precipitation 0.9 JulAugust: 0.71 in precipitation 0.7 AugSeptember: 1.08 in precipitation 1.1 SepOctober: 2.55 in precipitation 2.5 OctNovember: 3.85 in precipitation 3.9 NovDecember: 5.01 in precipitation 5.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Spokane Felts Field, WA (12 mi away); precipitation: Coeur D'Alene 6.6 Ssw, ID (10 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

990166b
Greenacres, WA · 3 mi
990276b
Otis Orchards, WA · 6 mi
990377a
Veradale, WA · 6 mi
990236b
Mica, WA · 6 mi
992167a
Spokane, WA · 7 mi
838546b
Post Falls, ID · 8 mi
838776b
Post Falls, ID · 8 mi
992067a
Spokane, WA · 8 mi

Washington planting zones →

Questions about 99019

What planting zone is ZIP code 99019?

ZIP code 99019 (Liberty Lake, 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 Liberty Lake, WA?

The median last spring frost (32 °F) near 99019 is April 26; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Spokane Felts Field station.

When is the first frost in Liberty Lake, WA?

The median first fall frost near 99019 is October 15, giving a median frost-free growing season of 170 days.

When should I plant tomatoes in 99019?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 99019 get?

About 29.4 inches of precipitation a year (NOAA 1991–2020 normals, Coeur D'Alene 6.6 Ssw station).

How hot do summers get in Liberty Lake, WA?

The average high peaks at 87 °F in July, with about 29 days a year at 90 °F or more.

What kind of soil does 99019 have?

The USDA soil survey maps Kellerbutte at the center of ZIP 99019: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Liberty Lake, WA in 2026?

Spring leaf-out near 99019 came on Apr 2 in 2026, 7 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Liberty Lake, WA?

Long-day onions: the longest day near 99019 is 15 h 59 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).