Oklahoma climate

Oklahoma Plant Hardiness Zones

Oklahoma’s towns run from zone 6b to zone 8a: the average coldest winter night is 13.7°F at Calera and -2.8°F at Boise City.

Hardiness zones in Oklahoma

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 Oklahoma, from zone 6b to zone 8b, with the state’s border drawn.
  • 6b
  • 7a
  • 7b
  • 8a
  • 8b

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.

8a Zone 8a, 10 to 15°F 45 towns

7b Zone 7b, 5 to 10°F 217 towns

7a Zone 7a, 0 to 5°F 86 towns

6b Zone 6b, -5 to 0°F 7 towns

Counties

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

CountyZone at the centerAverage coldest night
Adair County7a4.9°F
Alfalfa County7a2.5°F
Atoka County8a10.3°F
Beaver County6b-1.6°F
Beckham County7a4.9°F
Blaine County7b5.7°F
Bryan County8a12.7°F
Caddo County7b7.2°F
Canadian County7b7°F
Carter County8a11.4°F
Cherokee County7b6°F
Choctaw County8a13.2°F
Cimarron County6b-2.7°F
Cleveland County7b8.1°F
Coal County7b8.8°F
Comanche County8a10.6°F
Cotton County8a11.3°F
Craig County7a2.1°F
Creek County7b6.5°F
Custer County7b5.6°F
Delaware County7a4.2°F
Dewey County7a3.1°F
Ellis County7a0.7°F
Garfield County7a4.6°F
Garvin County7b9.1°F
Grady County7b7.5°F
Grant County7a2.7°F
Greer County7b6.7°F
Harmon County7b7°F
Harper County7a1°F
Haskell County7b8.6°F
Hughes County7b9°F
Jackson County7b9.1°F
Jefferson County8a11.3°F
Johnston County8a10.2°F
Kay County7a3.1°F
Kingfisher County7b5.3°F
Kiowa County7b7.9°F
Latimer County7b8.5°F
LeFlore County7b8.6°F
Lincoln County7b6.1°F
Logan County7b5.1°F
Love County8a12.2°F
Major County7a4.2°F
Marshall County8a12.4°F
Mayes County7a3.8°F
McClain County7b8.2°F
McCurtain County8a11.3°F
McIntosh County7b9.1°F
Murray County7b9.4°F
Muskogee County7b8.3°F
Noble County7a4°F
Nowata County7a1.6°F
Okfuskee County7b9.7°F
Oklahoma County7b7.7°F
Okmulgee County7b6.6°F
Osage County7a2.8°F
Ottawa County7a2.6°F
Pawnee County7a4.1°F
Payne County7a4.4°F
Pittsburg County7b9.2°F
Pontotoc County7b9.5°F
Pottawatomie County7b7.8°F
Pushmataha County8a10.1°F
Roger Mills County7a4.5°F
Rogers County7b5.2°F
Seminole County7b7.7°F
Sequoyah County7b8.9°F
Stephens County8a10.1°F
Texas County6b-0.4°F
Tillman County8a12.2°F
Tulsa County7b7.5°F
Wagoner County7b7.6°F
Washington County7a2.6°F
Washita County7b6.8°F
Woods County7a0.1°F
Woodward County7a1°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
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

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.