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

Planting zone for 99159 — Odessa, WA

ZIP code 99159 (Odessa, Lincoln County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 14 and the first fall frost September 26.

Where ZIP 99159 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 frostMay 14

First frostSep 26

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 Odessa, 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 Odessa, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 14median — 50% chance of a later frost

Safe for tender plantsMay 31only 10% chance of frost after

First fall frostSeptember 26median — 10% chance by Sep 10

Growing season135 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 7.

From the NOAA station Odessa, WA — 3 miles away, elevation 1,542 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 99159

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 2 – Apr 16

SpinachSow outdoors · Apr 2 – Apr 23

Broccoli, cabbageStart indoors · Mar 5 – Mar 19

Broccoli, cabbageTransplant · Apr 23 – May 7

Onion setsPlant outdoors · Apr 16 – Apr 30

PotatoesPlant outdoors · Apr 23 – May 7

LettuceSow outdoors · Apr 16 – Apr 30

Carrots, beetsSow outdoors · Apr 23 – May 7

TomatoesStart indoors · Mar 19 – Apr 2

TomatoesTransplant · May 21 – Jun 4

Peppers, eggplantStart indoors · Mar 5 – Mar 19

Peppers, eggplantTransplant · May 28 – Jun 11

BeansSow outdoors · May 21 – Jun 4

Sweet cornSow outdoors · May 21 – Jun 4

Cucumbers, squashSow outdoors · May 21 – Jun 4

Fall lettuce, spinachSow outdoors · Aug 1 – Aug 15

GarlicPlant cloves · Sep 12 – Oct 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 14) and first fall frost (Sep 26) 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 99159 came on Mar 23 — 7 days earlier than the 1991–2020 average (Mar 30).

average
Mar 302026
Mar 23

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 Odessa, WA.

Soil in Odessa, WA

The soil mapped at the center of ZIP 99159 is Roloff — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH7.0neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Roloff-Bakeoven-Rock outcrop complex, 0 to 15 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 99159; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Odessa, WA

Summer high88 °Faverage high, July

Winter low22 °Faverage low, December

Hot days34days a year at 90 °F or more

Freezing nights139nights a year at 32 °F or less

Growing degree days2,250base 50 °F — the season’s usable heat

Longest day15 h 57 mindaylight on June 21

Shortest day8 h 28 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

Snowfall14 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Odessa, WA (3 mi away); precipitation: Odessa, WA (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

Wilson Creek, WA · 19 mi

991546b

Mohler, WA · 20 mi

991696b

Ritzville, WA · 23 mi

991346b

Harrington, WA · 24 mi

991176b

Creston, WA · 24 mi

988536b

Stratford, WA · 26 mi

Washington planting zones →

Questions about 99159

What planting zone is ZIP code 99159?

ZIP code 99159 (Odessa, 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 Odessa, WA?

The median last spring frost (32 °F) near 99159 is May 14; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Odessa station.

When is the first frost in Odessa, WA?

The median first fall frost near 99159 is September 26, giving a median frost-free growing season of 135 days.

When should I plant tomatoes in 99159?

Start tomato seeds indoors around Mar 19 – Apr 2 and set transplants outside around May 21 – Jun 4, one to three weeks after the median last frost.

How much rain and snow does 99159 get?

About 11.1 inches of precipitation a year and 14 inches of snowfall (NOAA 1991–2020 normals, Odessa station).

How hot do summers get in Odessa, WA?

The average high peaks at 88 °F in July, with about 34 days a year at 90 °F or more.

What kind of soil does 99159 have?

The USDA soil survey maps Roloff at the center of ZIP 99159: silt loam, well drained, pH about 7.0 (neutral).

Did spring come early in Odessa, WA in 2026?

Spring leaf-out near 99159 came on Mar 23 in 2026, 7 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Odessa, WA?

Long-day onions: the longest day near 99159 is 15 h 57 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99159 change?

Yes. The 2012 USDA map put 99159 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.