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

Planting zone for Gresham, OR

Gresham, OR is in USDA zones 8b to 9a across its 2 ZIP codes. The median last spring frost is March 16 and the first fall frost November 20.

Gresham on the zone map

Outlined: its 2 ZIP code areas · 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.

Zones8b–9a15 to 25 °F

ZIP codes2

Last frostMar 16

First frostNov 20

Growing season250 days

8b 1 ZIP 9a 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Gresham, 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 Gresham, OR

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 16median — 50% chance of a later frost

Safe for tender plantsApril 12only 10% chance of frost after

First fall frostNovember 20median — 10% chance by Oct 30

Growing season250 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 14 and returns around December 15.

From the NOAA station Portland Troutdale Airport, OR, elevation 30 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 Gresham

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 2 – Feb 16

SpinachSow outdoors · Feb 2 – Feb 23

Broccoli, cabbageStart indoors · Jan 5 – Jan 19

Broccoli, cabbageTransplant · Feb 23 – Mar 9

Onion setsPlant outdoors · Feb 16 – Mar 2

PotatoesPlant outdoors · Feb 23 – Mar 9

LettuceSow outdoors · Feb 16 – Mar 2

Carrots, beetsSow outdoors · Feb 23 – Mar 9

TomatoesStart indoors · Jan 19 – Feb 2

TomatoesTransplant · Mar 23 – Apr 6

Peppers, eggplantStart indoors · Jan 5 – Jan 19

Peppers, eggplantTransplant · Mar 30 – Apr 13

BeansSow outdoors · Mar 23 – Apr 6

Sweet cornSow outdoors · Mar 23 – Apr 6

Cucumbers, squashSow outdoors · Mar 23 – Apr 6

Fall lettuce, spinachSow outdoors · Sep 25 – Oct 9

GarlicPlant cloves · Nov 6 – Dec 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 16) and first fall frost (Nov 20) 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 97030 came on Feb 7 — 11 days earlier than the 1991–2020 average (Feb 18).

average
Feb 182026
Feb 7

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 Gresham, OR.

Soil in Gresham, OR

The soil mapped at the center of ZIP 97030 is Multnomah — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter5%high

Hydrologic groupBwater soaks in moderately

Farmland classprime farmlandUSDA classification

Map unit: Multnomah silt loam, 0 to 3 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 97030; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Gresham, OR

Summer high82 °Faverage high, July

Winter low37 °Faverage low, January

Hot days16days a year at 90 °F or more

Freezing nights28nights a year at 32 °F or less

Growing degree days2,697base 50 °F — the season’s usable heat

Longest day15 h 41 mindaylight on June 21

Shortest day8 h 42 mindaylight on December 21

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

Precipitation40.7 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: Portland Troutdale Airport, OR (3 mi away); precipitation: Portland Troutdale Airport, OR (3 mi away). Daylight is calculated from latitude.

ZIP codes in Gresham

Oregon planting zones →

Questions about Gresham

What planting zone is Gresham, OR?

Gresham, OR is in USDA hardiness zones 8b to 9a on the 2023 map (8b: 15 to 20 °F; 9a: 20 to 25 °F).

When is the last frost in Gresham, OR?

The median last spring frost is March 16 and the median first fall frost is November 20 (NOAA 1991–2020 normals, Portland Troutdale Airport station).

When can I plant a garden in Gresham, OR?

Cool-season crops like peas and spinach go in around Feb 2 – Feb 23; tomatoes, peppers, beans and squash after about Mar 23, once frost risk has passed.

What kind of onions grow in Gresham, OR?

Long-day onions: the longest day is 15 h 41 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Gresham, OR get?

About 40.7 inches of precipitation a year (NOAA 1991–2020 normals).