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

Planting zone for 97835 — Helix, OR

ZIP code 97835 (Helix, 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 97835 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 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Helix, 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 Helix, 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 — 14 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 97835

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 97835 came on Mar 10 — about the same time as the 1991–2020 average (Mar 11).

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.

Trees 40

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °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 °FBrewer spruce100 ft · blooms early summer · low shade tolerance · to −13 °F

Shrubs 119

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 290

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 164

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 2

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Helix, OR.

Soil in Helix, OR

The soil mapped at the center of ZIP 97835 is Walla Walla — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Walla Walla silt loam, 12 to 25 percent north 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 97835; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Helix, OR

Summer high90 °Faverage high, July
Winter low26 °Faverage low, December
Hot days39days a year at 90 °F or more
Freezing nights125nights a year at 32 °F or less
Growing degree days2,325base 50 °F — the season’s usable heat
Longest day15 h 44 mindaylight on June 21
Shortest day8 h 39 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation17.2 inper year, rain and melted snow
Snowfall15 inper year; 18 days with snow on the ground

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 43 °F, low 27 °F 43°27° JanFebruary: average high 47 °F, low 28 °F 47°28° FebMarch: average high 55 °F, low 31 °F 55°31° MarApril: average high 62 °F, low 35 °F 62°35° AprMay: average high 70 °F, low 42 °F 70°42° MayJune: average high 78 °F, low 47 °F 78°47° JunJuly: average high 90 °F, low 52 °F 90°52° JulAugust: average high 89 °F, low 50 °F 89°50° AugSeptember: average high 79 °F, low 43 °F 79°43° SepOctober: average high 65 °F, low 35 °F 65°35° OctNovember: average high 51 °F, low 30 °F 51°30° NovDecember: average high 42 °F, low 26 °F 42°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 1.93 in precipitation, 5.3 in snowfall 1.9❄5 JanFebruary: 1.56 in precipitation, 2.5 in snowfall 1.6❄3 FebMarch: 1.97 in precipitation, 0.6 in snowfall 2.0❄1 MarApril: 1.75 in precipitation 1.8 AprMay: 1.87 in precipitation 1.9 MayJune: 1.23 in precipitation 1.2 JunJuly: 0.35 in precipitation 0.3 JulAugust: 0.37 in precipitation 0.4 AugSeptember: 0.58 in precipitation 0.6 SepOctober: 1.29 in precipitation, 0.2 in snowfall 1.3 OctNovember: 2.14 in precipitation, 1.5 in snowfall 2.1❄2 NovDecember: 2.14 in precipitation, 4.8 in snowfall 2.1❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Pendleton Branch Exp Stn, OR (14 mi away); precipitation: Pendleton Branch Exp Stn, OR (14 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.

993637b
Wallula, WA · 11 mi
978137a
Athena, OR · 12 mi
993607a
Touchet, WA · 14 mi
978017a
Pendleton, OR · 16 mi
993377b
Kennewick, WA · 19 mi
978757a
Stanfield, OR · 19 mi
993237a
Burbank, WA · 21 mi
978267a
Echo, OR · 27 mi

Oregon planting zones →

Questions about 97835

What planting zone is ZIP code 97835?

ZIP code 97835 (Helix, 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 Helix, OR?

The median last spring frost (32 °F) near 97835 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 Helix, OR?

The median first fall frost near 97835 is September 27, giving a median frost-free growing season of 135 days.

When should I plant tomatoes in 97835?

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 97835 get?

About 17.2 inches of precipitation a year and 15 inches of snowfall (NOAA 1991–2020 normals, Pendleton Branch Exp Stn station).

How hot do summers get in Helix, OR?

The average high peaks at 90 °F in July, with about 39 days a year at 90 °F or more.

What kind of soil does 97835 have?

The USDA soil survey maps Walla Walla at the center of ZIP 97835: silt loam, well drained, pH about 7.2 (neutral).

Did spring come early in Helix, OR in 2026?

Spring leaf-out near 97835 came on Mar 10 in 2026, about the same as the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Helix, OR?

Long-day onions: the longest day near 97835 is 15 h 44 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).