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

Planting zone for 97420 — Coos Bay, OR

ZIP code 97420 (Coos Bay, Coos County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is February 21 and the first fall frost December 9.

Where ZIP 97420 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 frostFeb 21

First frostDec 9

2012 zone9a

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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Coos Bay, 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 Coos Bay, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 21median — 50% chance of a later frost

Safe for tender plantsMarch 25only 10% chance of frost after

First fall frostDecember 9median — 10% chance by Nov 12

Growing season294 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 4 and returns around December 22.

From the NOAA station North Bend Regional Airport, OR — 8 miles away, elevation 16 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 97420

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 10 – Jan 24

SpinachSow outdoors · Jan 10 – Jan 31

Broccoli, cabbageStart indoors · Dec 13 – Dec 27

Broccoli, cabbageTransplant · Jan 31 – Feb 14

Onion setsPlant outdoors · Jan 24 – Feb 7

PotatoesPlant outdoors · Jan 31 – Feb 14

LettuceSow outdoors · Jan 24 – Feb 7

Carrots, beetsSow outdoors · Jan 31 – Feb 14

TomatoesStart indoors · Dec 27 – Jan 10

TomatoesTransplant · Feb 28 – Mar 14

Peppers, eggplantStart indoors · Dec 13 – Dec 27

Peppers, eggplantTransplant · Mar 7 – Mar 21

BeansSow outdoors · Feb 28 – Mar 14

Sweet cornSow outdoors · Feb 28 – Mar 14

Cucumbers, squashSow outdoors · Feb 28 – Mar 14

Fall lettuce, spinachSow outdoors · Oct 14 – Oct 28

GarlicPlant cloves · Nov 25 – Dec 30

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 21) and first fall frost (Dec 9) 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 97420 came on Feb 1 — 5 days earlier than the 1991–2020 average (Feb 6).

average
Feb 62026
Feb 1

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 Coos Bay, OR.

Soil in Coos Bay, OR

The soil mapped at the center of ZIP 97420 is Millicoma — 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 groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Millicoma-Templeton complex, 50 to 75 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 97420; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Coos Bay, OR

Summer high67 °Faverage high, August

Winter low40 °Faverage low, December

Hot days0days a year at 90 °F or more

Freezing nights10nights a year at 32 °F or less

Growing degree days1,631base 50 °F — the season’s usable heat

Longest day15 h 24 mindaylight on June 21

Shortest day8 h 58 mindaylight on December 21

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

Precipitation65.6 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: North Bend Regional Airport, OR (8 mi away); precipitation: Coos Bay 1 Nnw, OR (7 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.

974079a

Allegany, OR · 7 mi

974599a

North Bend, OR · 10 mi

Myrtle Point, OR · 21 mi

974119b

Bandon, OR · 23 mi

974739a

Scottsburg, OR · 26 mi

974149a

Broadbent, OR · 26 mi

Oregon planting zones →

Questions about 97420

What planting zone is ZIP code 97420?

ZIP code 97420 (Coos Bay, 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 Coos Bay, OR?

The median last spring frost (32 °F) near 97420 is February 21; after March 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, North Bend Regional Airport station.

When is the first frost in Coos Bay, OR?

The median first fall frost near 97420 is December 9, giving a median frost-free growing season of 294 days.

When should I plant tomatoes in 97420?

Start tomato seeds indoors around Dec 27 – Jan 10 and set transplants outside around Feb 28 – Mar 14, one to three weeks after the median last frost.

How much rain and snow does 97420 get?

About 65.6 inches of precipitation a year (NOAA 1991–2020 normals, Coos Bay 1 Nnw station).

How hot do summers get in Coos Bay, OR?

The average high peaks at 67 °F in August, with about 0 days a year at 90 °F or more.

What kind of soil does 97420 have?

The USDA soil survey maps Millicoma at the center of ZIP 97420: slightly decomposed plant material, well drained, pH about 4.5 (strongly acidic).

Did spring come early in Coos Bay, OR in 2026?

Spring leaf-out near 97420 came on Feb 1 in 2026, 5 days earlier than the 1991–2020 average (Feb 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Coos Bay, OR?

Long-day onions: the longest day near 97420 is 15 h 24 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).