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

Planting zone for 97390 — Tidewater, OR

ZIP code 97390 (Tidewater, Lincoln County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is April 13 and the first fall frost November 3.

Where ZIP 97390 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 frostApr 13

First frostNov 3

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 Tidewater, 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 Tidewater, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsMay 3only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 9

Growing season202 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 28 and returns around November 28.

From the NOAA station Alsea Fh (Fall Creek), OR — 6 miles away, elevation 230 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 97390

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 2 – Mar 16

SpinachSow outdoors · Mar 2 – Mar 23

Broccoli, cabbageStart indoors · Feb 2 – Feb 16

Broccoli, cabbageTransplant · Mar 23 – Apr 6

Onion setsPlant outdoors · Mar 16 – Mar 30

PotatoesPlant outdoors · Mar 23 – Apr 6

LettuceSow outdoors · Mar 16 – Mar 30

Carrots, beetsSow outdoors · Mar 23 – Apr 6

TomatoesStart indoors · Feb 16 – Mar 2

TomatoesTransplant · Apr 20 – May 4

Peppers, eggplantStart indoors · Feb 2 – Feb 16

Peppers, eggplantTransplant · Apr 27 – May 11

BeansSow outdoors · Apr 20 – May 4

Sweet cornSow outdoors · Apr 20 – May 4

Cucumbers, squashSow outdoors · Apr 20 – May 4

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 13) and first fall frost (Nov 3) 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 97390 came on Feb 5 — 7 days earlier than the 1991–2020 average (Feb 12).

average
Feb 122026
Feb 5

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 Tidewater, OR.

Soil in Tidewater, OR

The soil mapped at the center of ZIP 97390 is Bohannon — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH4.5strongly 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: Bohannon gravelly loam, dissected, 50 to 90 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 97390; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tidewater, OR

Summer high76 °Faverage high, August

Winter low35 °Faverage low, December

Hot days2days a year at 90 °F or more

Freezing nights53nights a year at 32 °F or less

Growing degree days1,498base 50 °F — the season’s usable heat

Longest day15 h 32 mindaylight on June 21

Shortest day8 h 50 mindaylight on December 21

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

Precipitation91.9 inper year, rain and melted snow

Snowfall1 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Alsea Fh (Fall Creek), OR (6 mi away); precipitation: Alsea Fh (Fall Creek), OR (6 mi away). 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.

Seal Rock, OR · 11 mi

Swisshome, OR · 16 mi

973919a

Toledo, OR · 16 mi

973439a

Eddyville, OR · 16 mi

Oregon planting zones →

Questions about 97390

What planting zone is ZIP code 97390?

ZIP code 97390 (Tidewater, 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 Tidewater, OR?

The median last spring frost (32 °F) near 97390 is April 13; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alsea Fh (Fall Creek) station.

When is the first frost in Tidewater, OR?

The median first fall frost near 97390 is November 3, giving a median frost-free growing season of 202 days.

When should I plant tomatoes in 97390?

Start tomato seeds indoors around Feb 16 – Mar 2 and set transplants outside around Apr 20 – May 4, one to three weeks after the median last frost.

How much rain and snow does 97390 get?

About 91.9 inches of precipitation a year and 1 inches of snowfall (NOAA 1991–2020 normals, Alsea Fh (Fall Creek) station).

How hot do summers get in Tidewater, OR?

The average high peaks at 76 °F in August, with about 2 days a year at 90 °F or more.

What kind of soil does 97390 have?

The USDA soil survey maps Bohannon at the center of ZIP 97390: slightly decomposed plant material, well drained, pH about 4.5 (strongly acidic).

Did spring come early in Tidewater, OR in 2026?

Spring leaf-out near 97390 came on Feb 5 in 2026, 7 days earlier than the 1991–2020 average (Feb 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tidewater, OR?

Long-day onions: the longest day near 97390 is 15 h 32 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 97390 change?

Yes. The 2012 USDA map put 97390 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.