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Planting zones · Portland, Oregon

What Planting Zone Is Portland?

Portland is in USDA zone 8b–9a. Marine west-coast climate: about 37 in. of rain, but only 7% of it falls July–September, so summer drought is real. Zones are 8b–9a, and a 32°F freeze occurs every winter (median last freeze March 13).

  • USDA zone (2023)8b–9a
  • Coldest night (avg.)20 to 25°FZIP 97204
  • Median last frostMar 1332°F
  • Median first frostNov 1932°F
  • Annual precipitation37 inches
  • Frost-free season247 days

Portland hardiness zone by ZIP code

On the 2023 USDA Plant Hardiness Zone Map, the ZIP codes we sampled in Portland fall in zones 8b to 9a; 97204 (zone 9a) has an average annual extreme minimum of 20 to 25°F. Choose perennials, shrubs, and trees rated at least to zone 8.

2023 USDA zone for sampled Portland ZIP codes
ZIPZoneAvg. coldest night
970068b15 to 20°F
972049a20 to 25°F
972149a20 to 25°F
972198b15 to 20°F
972298b15 to 20°F

Not listed? Look up any ZIP code.

Frost dates and when to plant

The median last spring frost (32°F) at Portland Intl Airport is Mar 13 and the median first fall frost is Nov 19, a typical frost-free season of about 247 days.

Plant container perennials and shrubs after the median last frost (Mar 13), or in early fall at least six weeks before the median first frost (Nov 19) so roots can settle in before the ground freezes.

Rainfall and heat in Portland

Average annual precipitation is 37 inches (Portland Intl Airport, 1991–2020), and 65% of it falls November–March. Summers are dry (July is the driest month), so plants lean on stored soil moisture and supplemental water through their first summer.

The average high in August is about 82°F and the average low in January is about 36°F, measured at about 20 ft.

That is why a zone rating alone isn't enough for a xeriscape here: pick plants that are both cold-hardy to zone 8 and rated very low or low water once established.

Low-water plants for Portland

82 plants in our database are hardy to zone 8 and suited to zone 8. Here are 12, driest first, across plant types.

See all zone 8 plants

Frequently asked questions

What planting zone is Portland?

Portland, OR is in USDA hardiness zone 8b–9a on the 2023 USDA Plant Hardiness Zone Map, based on the ZIP codes we sampled (97006: 8b, 97204: 9a, 97214: 9a, 97219: 8b, 97229: 8b). In 97204, the average coldest night of the year is 20 to 25°F.

When is the last frost in Portland?

The median last spring frost (32°F) at Portland Intl Airport is Mar 13 and the median first fall frost is Nov 19, a typical frost-free season of about 247 days.

How much rain does Portland get?

Average annual precipitation is 37 inches (Portland Intl Airport, 1991–2020), and 65% of it falls November–March. Summers are dry (July is the driest month), so plants lean on stored soil moisture and supplemental water through their first summer.

Sources

  1. NOAA NCEI U.S. Climate Normals 1991–2020, Portland Intl Airport (USW00024229). ncei.noaa.gov
  2. USDA ARS 2023 Plant Hardiness Zone Map, by ZIP. planthardiness.ars.usda.gov