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

Planting zone for 97446 — Harrisburg, OR

ZIP code 97446 (Harrisburg, Linn County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 11 and the first fall frost October 23.

Where ZIP 97446 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.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostApr 11

First frostOct 23

2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Harrisburg, 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 Harrisburg, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 11median — 50% chance of a later frost

Safe for tender plantsMay 9only 10% chance of frost after

First fall frostOctober 23median — 10% chance by Oct 6

Growing season196 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 3 and returns around November 11.

From the NOAA station Eugene Mahlon Sweet Airport, OR — 12 miles away, elevation 354 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 97446

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 28 – Mar 14

SpinachSow outdoors · Feb 28 – Mar 21

Broccoli, cabbageStart indoors · Jan 31 – Feb 14

Broccoli, cabbageTransplant · Mar 21 – Apr 4

Onion setsPlant outdoors · Mar 14 – Mar 28

PotatoesPlant outdoors · Mar 21 – Apr 4

LettuceSow outdoors · Mar 14 – Mar 28

Carrots, beetsSow outdoors · Mar 21 – Apr 4

TomatoesStart indoors · Feb 14 – Feb 28

TomatoesTransplant · Apr 18 – May 2

Peppers, eggplantStart indoors · Jan 31 – Feb 14

Peppers, eggplantTransplant · Apr 25 – May 9

BeansSow outdoors · Apr 18 – May 2

Sweet cornSow outdoors · Apr 18 – May 2

Cucumbers, squashSow outdoors · Apr 18 – May 2

Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11

GarlicPlant cloves · Oct 9 – Nov 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 23) 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 97446 came on Feb 28 — 10 days later than the 1991–2020 average (Feb 18).

average
Feb 182026
Feb 28

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 8b in Oregon

661 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. 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 Harrisburg, OR.

Soil in Harrisburg, OR

The soil mapped at the center of ZIP 97446 is Bashaw — silty clay, poorly drained.

TextureSilty clayholds water and nutrients; slow to drain and warm up

pH6.5neutral; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter6%high

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Bashaw silty clay.

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 97446; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Harrisburg, OR

Summer high84 °Faverage high, July

Winter low34 °Faverage low, December

Hot days18days a year at 90 °F or more

Freezing nights52nights a year at 32 °F or less

Growing degree days2,299base 50 °F — the season’s usable heat

Longest day15 h 31 mindaylight on June 21

Shortest day8 h 51 mindaylight on December 21

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

Precipitation53.2 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: Eugene Mahlon Sweet Airport, OR (12 mi away); precipitation: Springfield 8.3 Nne, OR (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8b.

Brownsville, OR · 10 mi

974048b

Eugene, OR · 11 mi

974488b

Junction City, OR · 12 mi

974548b

Marcola, OR · 12 mi

973368b

Crawfordsville, OR · 12 mi

974018b

Eugene, OR · 13 mi

Oregon planting zones →

Questions about 97446

What planting zone is ZIP code 97446?

ZIP code 97446 (Harrisburg, OR) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Harrisburg, OR?

The median last spring frost (32 °F) near 97446 is April 11; after May 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Eugene Mahlon Sweet Airport station.

When is the first frost in Harrisburg, OR?

The median first fall frost near 97446 is October 23, giving a median frost-free growing season of 196 days.

When should I plant tomatoes in 97446?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 97446 get?

About 53.2 inches of precipitation a year (NOAA 1991–2020 normals, Springfield 8.3 Nne station).

How hot do summers get in Harrisburg, OR?

The average high peaks at 84 °F in July, with about 18 days a year at 90 °F or more.

What kind of soil does 97446 have?

The USDA soil survey maps Bashaw at the center of ZIP 97446: silty clay, poorly drained, pH about 6.5 (neutral).

Did spring come early in Harrisburg, OR in 2026?

Spring leaf-out near 97446 came on Feb 28 in 2026, 10 days later than the 1991–2020 average (Feb 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Harrisburg, OR?

Long-day onions: the longest day near 97446 is 15 h 31 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).