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

Planting zone for 97844 — Irrigon, OR

ZIP code 97844 (Irrigon, Morrow County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 14 and the first fall frost October 21.

Where ZIP 97844 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.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostApr 14
First frostOct 21
2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Irrigon, 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 Irrigon, OR

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 14median — 50% chance of a later frost
Safe for tender plantsMay 2only 10% chance of frost after
First fall frostOctober 21median — 10% chance by Oct 5
Growing season188 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 28 and returns around November 1.

From the NOAA station Boardman, OR — 7 miles away, elevation 279 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 97844

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 3 – Mar 17
SpinachSow outdoors · Mar 3 – Mar 24
Broccoli, cabbageStart indoors · Feb 3 – Feb 17
Broccoli, cabbageTransplant · Mar 24 – Apr 7
Onion setsPlant outdoors · Mar 17 – Mar 31
PotatoesPlant outdoors · Mar 24 – Apr 7
LettuceSow outdoors · Mar 17 – Mar 31
Carrots, beetsSow outdoors · Mar 24 – Apr 7
TomatoesStart indoors · Feb 17 – Mar 3
TomatoesTransplant · Apr 21 – May 5
Peppers, eggplantStart indoors · Feb 3 – Feb 17
Peppers, eggplantTransplant · Apr 28 – May 12
BeansSow outdoors · Apr 21 – May 5
Sweet cornSow outdoors · Apr 21 – May 5
Cucumbers, squashSow outdoors · Apr 21 – May 5
Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9
GarlicPlant cloves · Oct 7 – Nov 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 14) and first fall frost (Oct 21) 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 97844 came on Mar 4 — 5 days earlier than the 1991–2020 average (Mar 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 7b in Oregon

627 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. 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 120

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 292

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 Irrigon, OR.

Soil in Irrigon, OR

The soil mapped at the center of ZIP 97844 is Winchester — sand, excessively drained.

TextureSanddrains and warms fast; dries out and needs more feeding
pH7.3neutral; most vegetables like 6.0–7.0
DrainageExcessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Winchester sand, 0 to 12 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 97844; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Irrigon, OR

Summer high91 °Faverage high, July
Winter low29 °Faverage low, January
Hot days46days a year at 90 °F or more
Freezing nights104nights a year at 32 °F or less
Growing degree days3,212base 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)
Precipitation8.6 inper year, rain and melted snow
Snowfall4 inper year

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 42 °F, low 29 °F 42°29° JanFebruary: average high 48 °F, low 30 °F 48°30° FebMarch: average high 58 °F, low 34 °F 58°34° MarApril: average high 66 °F, low 40 °F 66°40° AprMay: average high 75 °F, low 48 °F 75°48° MayJune: average high 82 °F, low 55 °F 82°55° JunJuly: average high 91 °F, low 60 °F 91°60° JulAugust: average high 90 °F, low 59 °F 90°59° AugSeptember: average high 81 °F, low 50 °F 81°50° SepOctober: average high 66 °F, low 40 °F 66°40° OctNovember: average high 51 °F, low 33 °F 51°33° NovDecember: average high 42 °F, low 29 °F 42°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 1.28 in precipitation, 1.2 in snowfall 1.3❄1 JanFebruary: 0.92 in precipitation, 1.4 in snowfall 0.9❄1 FebMarch: 0.70 in precipitation, 0.2 in snowfall 0.7 MarApril: 0.64 in precipitation 0.6 AprMay: 0.80 in precipitation 0.8 MayJune: 0.55 in precipitation 0.6 JunJuly: 0.14 in precipitation 0.1 JulAugust: 0.18 in precipitation 0.2 AugSeptember: 0.25 in precipitation 0.3 SepOctober: 0.74 in precipitation, 0.1 in snowfall 0.7 OctNovember: 0.98 in precipitation 1.0 NovDecember: 1.38 in precipitation, 0.8 in snowfall 1.4❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Boardman, OR (7 mi away); precipitation: Boardman, 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.

993457b
Paterson, WA · 6 mi
978827b
Umatilla, OR · 10 mi
978387b
Hermiston, OR · 13 mi
978187b
Boardman, OR · 14 mi
993467b
Plymouth, WA · 16 mi
993507b
Prosser, WA · 20 mi
978397a
Lexington, OR · 22 mi
993387b
Kennewick, WA · 24 mi

Oregon planting zones →

Questions about 97844

What planting zone is ZIP code 97844?

ZIP code 97844 (Irrigon, OR) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Irrigon, OR?

The median last spring frost (32 °F) near 97844 is April 14; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Boardman station.

When is the first frost in Irrigon, OR?

The median first fall frost near 97844 is October 21, giving a median frost-free growing season of 188 days.

When should I plant tomatoes in 97844?

Start tomato seeds indoors around Feb 17 – Mar 3 and set transplants outside around Apr 21 – May 5, one to three weeks after the median last frost.

How much rain and snow does 97844 get?

About 8.6 inches of precipitation a year and 4 inches of snowfall (NOAA 1991–2020 normals, Boardman station).

How hot do summers get in Irrigon, OR?

The average high peaks at 91 °F in July, with about 46 days a year at 90 °F or more.

What kind of soil does 97844 have?

The USDA soil survey maps Winchester at the center of ZIP 97844: sand, excessively drained, pH about 7.3 (neutral).

Did spring come early in Irrigon, OR in 2026?

Spring leaf-out near 97844 came on Mar 4 in 2026, 5 days earlier than the 1991–2020 average (Mar 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Irrigon, OR?

Long-day onions: the longest day near 97844 is 15 h 44 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 97844 change?

Yes. The 2012 USDA map put 97844 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.