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

Planting zone for 97810 — Adams, OR

ZIP code 97810 (Adams, Umatilla County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 12 and the first fall frost September 27.

Where ZIP 97810 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostMay 12

First frostSep 27

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Adams, 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 Adams, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 12median — 50% chance of a later frost

Safe for tender plantsJune 2only 10% chance of frost after

First fall frostSeptember 27median — 10% chance by Sep 8

Growing season135 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 10.

From the NOAA station Pendleton Branch Exp Stn, OR — 12 miles away, elevation 1,486 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 97810

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 31 – Apr 14

SpinachSow outdoors · Mar 31 – Apr 21

Broccoli, cabbageStart indoors · Mar 3 – Mar 17

Broccoli, cabbageTransplant · Apr 21 – May 5

Onion setsPlant outdoors · Apr 14 – Apr 28

PotatoesPlant outdoors · Apr 21 – May 5

LettuceSow outdoors · Apr 14 – Apr 28

Carrots, beetsSow outdoors · Apr 21 – May 5

TomatoesStart indoors · Mar 17 – Mar 31

TomatoesTransplant · May 19 – Jun 2

Peppers, eggplantStart indoors · Mar 3 – Mar 17

Peppers, eggplantTransplant · May 26 – Jun 9

BeansSow outdoors · May 19 – Jun 2

Sweet cornSow outdoors · May 19 – Jun 2

Cucumbers, squashSow outdoors · May 19 – Jun 2

Fall lettuce, spinachSow outdoors · Aug 2 – Aug 16

GarlicPlant cloves · Sep 13 – Oct 18

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Sep 27) 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 97810 came on Mar 4 — 21 days earlier than the 1991–2020 average (Mar 25).

average
Mar 252026
Mar 4

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 7a in Oregon

624 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Adams, OR.

Soil in Adams, OR

The soil mapped at the center of ZIP 97810 is Umatilla — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Umatilla-Kahler-Gwin association, 35 to 70 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 97810; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Adams, OR

Summer high79 °Faverage high, July

Winter low20 °Faverage low, December

Hot days7days a year at 90 °F or more

Freezing nights212nights a year at 32 °F or less

Growing degree days953base 50 °F — the season’s usable heat

Longest day15 h 42 mindaylight on June 21

Shortest day8 h 41 mindaylight on December 21

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

Precipitation34.6 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: Meacham, OR (11 mi away); precipitation: Emigrant Springs, OR (8 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.

Milton Freewater, OR · 18 mi

978766b

Summerville, OR · 21 mi

978017a

Pendleton, OR · 21 mi

978357a

Helix, OR · 24 mi

993247a

College Place, WA · 26 mi

Oregon planting zones →

Questions about 97810

What planting zone is ZIP code 97810?

ZIP code 97810 (Adams, OR) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Adams, OR?

The median last spring frost (32 °F) near 97810 is May 12; after June 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Pendleton Branch Exp Stn station.

When is the first frost in Adams, OR?

The median first fall frost near 97810 is September 27, giving a median frost-free growing season of 135 days.

When should I plant tomatoes in 97810?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 97810 get?

About 34.6 inches of precipitation a year (NOAA 1991–2020 normals, Emigrant Springs station).

How hot do summers get in Adams, OR?

The average high peaks at 79 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 97810 have?

The USDA soil survey maps Umatilla at the center of ZIP 97810: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Adams, OR in 2026?

Spring leaf-out near 97810 came on Mar 4 in 2026, 21 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Adams, OR?

Long-day onions: the longest day near 97810 is 15 h 42 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 97810 change?

Yes. The 2012 USDA map put 97810 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.