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

Planting zone for 98508 — Olympia, WA

ZIP code 98508 (Olympia, Thurston County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 29 and the first fall frost October 14.

Where ZIP 98508 is

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.

Zone8b15 to 20 °F
Coldest night−9.4 to −6.7 °C
Last frostApr 29
First frostOct 14
2012 zone8a

Was 8a 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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Olympia, 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 Olympia, WA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 29median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 14median — 10% chance by Sep 28
Growing season169 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around November 1.

From the NOAA station Olympia Airport, WA — 4 miles away, elevation 187 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 98508

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 18 – Apr 1
SpinachSow outdoors · Mar 18 – Apr 8
Broccoli, cabbageStart indoors · Feb 18 – Mar 4
Broccoli, cabbageTransplant · Apr 8 – Apr 22
Onion setsPlant outdoors · Apr 1 – Apr 15
PotatoesPlant outdoors · Apr 8 – Apr 22
LettuceSow outdoors · Apr 1 – Apr 15
Carrots, beetsSow outdoors · Apr 8 – Apr 22
TomatoesStart indoors · Mar 4 – Mar 18
TomatoesTransplant · May 6 – May 20
Peppers, eggplantStart indoors · Feb 18 – Mar 4
Peppers, eggplantTransplant · May 13 – May 27
BeansSow outdoors · May 6 – May 20
Sweet cornSow outdoors · May 6 – May 20
Cucumbers, squashSow outdoors · May 6 – May 20
Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2
GarlicPlant cloves · Sep 30 – Nov 4
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 14) 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 98508 came on Feb 24 — 3 days earlier than the 1991–2020 average (Feb 27).

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 8b in Washington

614 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. Each links to its USDA PLANTS profile.

Trees 32

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 114

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 293

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 Olympia, WA.

Soil in Olympia, WA

The soil mapped at the center of ZIP 98508 is Skipopa — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter6%high
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Skipopa silt loam, 3 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 98508; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Olympia, WA

Summer high78 °Faverage high, July
Winter low32 °Faverage low, February
Hot days6days a year at 90 °F or more
Freezing nights77nights a year at 32 °F or less
Growing degree days1,723base 50 °F — the season’s usable heat
Longest day15 h 54 mindaylight on June 21
Shortest day8 h 30 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation59 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°32 °FJanuary: average high 46 °F, low 33 °F 46°33° JanFebruary: average high 49 °F, low 32 °F 49°32° FebMarch: average high 54 °F, low 35 °F 54°35° MarApril: average high 59 °F, low 38 °F 59°38° AprMay: average high 66 °F, low 43 °F 66°43° MayJune: average high 71 °F, low 47 °F 71°47° JunJuly: average high 78 °F, low 51 °F 78°51° JulAugust: average high 78 °F, low 51 °F 78°51° AugSeptember: average high 72 °F, low 46 °F 72°46° SepOctober: average high 60 °F, low 41 °F 60°41° OctNovember: average high 51 °F, low 36 °F 51°36° NovDecember: average high 45 °F, low 33 °F 45°33° Dec

Precipitation by month inches

0″2″4″6″8″10″January: 8.87 in precipitation 8.9 JanFebruary: 5.74 in precipitation 5.7 FebMarch: 6.39 in precipitation 6.4 MarApril: 4.24 in precipitation 4.2 AprMay: 2.52 in precipitation 2.5 MayJune: 1.85 in precipitation 1.9 JunJuly: 0.66 in precipitation 0.7 JulAugust: 1.10 in precipitation 1.1 AugSeptember: 2.16 in precipitation 2.2 SepOctober: 6.19 in precipitation 6.2 OctNovember: 9.67 in precipitation 9.7 NovDecember: 9.62 in precipitation 9.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Olympia Airport, WA (4 mi away); precipitation: Olympia 1.3 S, WA (within 1 mile). 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.

985048b
Olympia, WA · <1 mi
985078b
Olympia, WA · <1 mi
985998b
Olympia, WA · <1 mi
985058b
Olympia, WA · 4 mi
985018a
Olympia, WA · 4 mi
985068b
Olympia, WA · 5 mi
985038b
Lacey, WA · 5 mi
985028b
Olympia, WA · 7 mi

All 11 ZIP codes in Olympia → · Washington planting zones →

Questions about 98508

What planting zone is ZIP code 98508?

ZIP code 98508 (Olympia, WA) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Olympia, WA?

The median last spring frost (32 °F) near 98508 is April 29; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Olympia Airport station.

When is the first frost in Olympia, WA?

The median first fall frost near 98508 is October 14, giving a median frost-free growing season of 169 days.

When should I plant tomatoes in 98508?

Start tomato seeds indoors around Mar 4 – Mar 18 and set transplants outside around May 6 – May 20, one to three weeks after the median last frost.

How much rain and snow does 98508 get?

About 59 inches of precipitation a year (NOAA 1991–2020 normals, Olympia 1.3 S station).

How hot do summers get in Olympia, WA?

The average high peaks at 78 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 98508 have?

The USDA soil survey maps Skipopa at the center of ZIP 98508: silt loam, somewhat poorly drained, pH about 6.1 (slightly acidic).

Did spring come early in Olympia, WA in 2026?

Spring leaf-out near 98508 came on Feb 24 in 2026, 3 days earlier than the 1991–2020 average (Feb 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Olympia, WA?

Long-day onions: the longest day near 98508 is 15 h 54 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 98508 change?

Yes. The 2012 USDA map put 98508 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.