Oregon climate

Oregon Plant Hardiness Zones

Oregon’s towns run from zone 5b to zone 10a: the average coldest winter night is 31.2°F at Harbor and -10.8°F at Burns.

Hardiness zones in Oregon

In USDA’s colors, neighboring states washed out. Zones follow elevation, coasts and cities down to half a mile. Drawn by WeatherOverTime from the USDA-ARS and Oregon State University PRISM Climate Group 2023 GIS data; this is not the official USDA Plant Hardiness Zone Map.

Map of the 2023 plant hardiness zones across Oregon, from zone 5a to zone 10a, with the state’s border drawn.
  • 5a
  • 5b
  • 6a
  • 6b
  • 7a
  • 7b
  • 8a
  • 8b
  • 9a
  • 9b
  • 10a

Open the live map with plant hardiness zones

Towns by zone

Each town’s 1991-2020 average annual extreme minimum at its center, read from the map’s 800 m grid. Warmest zone first.

10a Zone 10a, 30 to 35°F 2 towns

9b Zone 9b, 25 to 30°F 20 towns

9a Zone 9a, 20 to 25°F 71 towns

8b Zone 8b, 15 to 20°F 106 towns

8a Zone 8a, 10 to 15°F 6 towns

7b Zone 7b, 5 to 10°F 8 towns

7a Zone 7a, 0 to 5°F 20 towns

6b Zone 6b, -5 to 0°F 19 towns

6a Zone 6a, -10 to -5°F 8 towns

5b Zone 5b, -15 to -10°F 2 towns

Counties

At the county’s center; a county with hills or a coast spans several zones.

CountyZone at the centerAverage coldest night
Baker County6b-3.9°F
Benton County8b16.6°F
Clackamas County8b17.6°F
Clatsop County8b17.8°F
Columbia County8b17.1°F
Coos County9a23.1°F
Crook County6b-4.8°F
Curry County9b25.4°F
Deschutes County6b-0.5°F
Douglas County8b19.1°F
Gilliam County7a2.5°F
Grant County6b-0.8°F
Harney County6b-4.8°F
Hood River County7b7.6°F
Jackson County8b15°F
Jefferson County7a1.2°F
Josephine County8b16.7°F
Klamath County6a-5.2°F
Lake County7a0°F
Lane County8b19.6°F
Lincoln County9a24.6°F
Linn County8b17.8°F
Malheur County7a1.2°F
Marion County8a14.8°F
Morrow County7a3.2°F
Multnomah County9a22.3°F
Polk County8b18.1°F
Sherman County7a2.2°F
Tillamook County9a22.5°F
Umatilla County7a2°F
Union County6b-0.4°F
Wallowa County6b-3.1°F
Wasco County7a3.5°F
Washington County8b17.4°F
Wheeler County7a1.8°F
Yamhill County9a21.4°F

The zones

A plant hardiness zone is set by the average of each winter’s single coldest temperature, 1991 to 2020: zones are 10°F apart and each half zone, a and b, 5°F. It says how cold a winter night usually gets, not the coldest it has ever been, and nothing about summer heat, rain or soil. Plant labels give the coldest zone a perennial survives in.

ZoneAverage coldest nightIn Celsius
5b-15 to -10°F-26.1 to -23.3°C
6a-10 to -5°F-23.3 to -20.6°C
6b-5 to 0°F-20.6 to -17.8°C
7a0 to 5°F-17.8 to -15.0°C
7b5 to 10°F-15.0 to -12.2°C
8a10 to 15°F-12.2 to -9.4°C
8b15 to 20°F-9.4 to -6.7°C
9a20 to 25°F-6.7 to -3.9°C
9b25 to 30°F-3.9 to -1.1°C
10a30 to 35°F-1.1 to 1.7°C

Sources

Hardiness zones: USDA Plant Hardiness Zone Map, 2023, Agricultural Research Service, U.S. Department of Agriculture, from the GIS data of the PRISM Climate Group, Oregon State University, which may be freely reproduced and redistributed. Drawn by WeatherOverTime from the USDA-ARS and Oregon State University PRISM Climate Group 2023 GIS data; this is not the official USDA Plant Hardiness Zone Map.