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

Planting zone for 97230 — Portland, OR

ZIP code 97230 (Portland, Multnomah County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 13 and the first fall frost November 22.

Where ZIP 97230 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.

Zone9a20 to 25 °F

Coldest night−6.7 to −3.9 °C

Last frostMar 13

First frostNov 22

2012 zone8b

Was 8b 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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Portland, OR…

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 Portland, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 13median — 50% chance of a later frost

Safe for tender plantsApril 5only 10% chance of frost after

First fall frostNovember 22median — 10% chance by Nov 3

Growing season251 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 12 and returns around December 10.

From the NOAA station Portland WFO, OR — 2 miles away, elevation 20 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 97230

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 30 – Feb 13

SpinachSow outdoors · Jan 30 – Feb 20

Broccoli, cabbageStart indoors · Jan 2 – Jan 16

Broccoli, cabbageTransplant · Feb 20 – Mar 6

Onion setsPlant outdoors · Feb 13 – Feb 27

PotatoesPlant outdoors · Feb 20 – Mar 6

LettuceSow outdoors · Feb 13 – Feb 27

Carrots, beetsSow outdoors · Feb 20 – Mar 6

TomatoesStart indoors · Jan 16 – Jan 30

TomatoesTransplant · Mar 20 – Apr 3

Peppers, eggplantStart indoors · Jan 2 – Jan 16

Peppers, eggplantTransplant · Mar 27 – Apr 10

BeansSow outdoors · Mar 20 – Apr 3

Sweet cornSow outdoors · Mar 20 – Apr 3

Cucumbers, squashSow outdoors · Mar 20 – Apr 3

Fall lettuce, spinachSow outdoors · Sep 27 – Oct 11

GarlicPlant cloves · Nov 8 – Dec 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 13) and first fall frost (Nov 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 97230 came on Feb 9 — 9 days earlier than the 1991–2020 average (Feb 18).

average
Feb 182026
Feb 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 9a in Oregon

666 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 20 °F or colder — the bottom of zone 9a. 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 Portland, OR.

Soil in Portland, OR

The soil mapped at the center of ZIP 97230 is Sauvie — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables

pH6.1slightly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter3%moderate

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if drainedUSDA classification

Map unit: Sauvie silty clay loam, protected.

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 97230; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Portland, OR

Summer high82 °Faverage high, July

Winter low36 °Faverage low, December

Hot days16days a year at 90 °F or more

Freezing nights29nights a year at 32 °F or less

Growing degree days2,677base 50 °F — the season’s usable heat

Longest day15 h 42 mindaylight on June 21

Shortest day8 h 42 mindaylight on December 21

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

Precipitation43.7 inper year, rain and melted snow

Snowfall3 inper year; 2 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Portland WFO, OR (2 mi away); precipitation: Portland WFO, OR (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

All 59 ZIP codes in Portland → · Oregon planting zones →

Questions about 97230

What planting zone is ZIP code 97230?

ZIP code 97230 (Portland, OR) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Portland, OR?

The median last spring frost (32 °F) near 97230 is March 13; after April 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Portland WFO station.

When is the first frost in Portland, OR?

The median first fall frost near 97230 is November 22, giving a median frost-free growing season of 251 days.

When should I plant tomatoes in 97230?

Start tomato seeds indoors around Jan 16 – Jan 30 and set transplants outside around Mar 20 – Apr 3, one to three weeks after the median last frost.

How much rain and snow does 97230 get?

About 43.7 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Portland WFO station).

How hot do summers get in Portland, OR?

The average high peaks at 82 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 97230 have?

The USDA soil survey maps Sauvie at the center of ZIP 97230: silt loam, poorly drained, pH about 6.1 (slightly acidic).

Did spring come early in Portland, OR in 2026?

Spring leaf-out near 97230 came on Feb 9 in 2026, 9 days earlier than the 1991–2020 average (Feb 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Portland, OR?

Long-day onions: the longest day near 97230 is 15 h 42 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 97230 change?

Yes. The 2012 USDA map put 97230 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.