USDA hardiness zones
Each zone is 10°F wide, split into a colder "a" half and a warmer "b" half, based on the average coldest winter night from 1991 to 2020.
| Zone | Average coldest night | ZIP codes | Where you find it |
|---|---|---|---|
| 1a | -60 to -55°F (-51 to -48°C) | 5 | Alaska |
| 1b | -55 to -50°F (-48 to -46°C) | 11 | Alaska |
| 2a | -50 to -45°F (-46 to -43°C) | 27 | Alaska |
| 2b | -45 to -40°F (-43 to -40°C) | 17 | Alaska |
| 3a | -40 to -35°F (-40 to -37°C) | 23 | Alaska, Minnesota |
| 3b | -35 to -30°F (-37 to -34°C) | 230 | Minnesota, North Dakota, Alaska, Montana |
| 4a | -30 to -25°F (-34 to -32°C) | 814 | North Dakota, Minnesota, Wisconsin, Montana |
| 4b | -25 to -20°F (-32 to -29°C) | 1,284 | Minnesota, Wisconsin, South Dakota, Montana |
| 5a | -20 to -15°F (-29 to -26°C) | 2,426 | Iowa, Minnesota, Wisconsin, Vermont |
| 5b | -15 to -10°F (-26 to -23°C) | 2,880 | Illinois, New York, Iowa, Nebraska |
| 6a | -10 to -5°F (-23 to -21°C) | 5,187 | Illinois, Michigan, Indiana, Ohio |
| 6b | -5 to 0°F (-21 to -18°C) | 5,271 | Ohio, Pennsylvania, Missouri, Kansas |
| 7a | 0 to 5°F (-18 to -15°C) | 4,877 | Kentucky, Pennsylvania, West Virginia, Virginia |
| 7b | 5 to 10°F (-15 to -12°C) | 3,855 | Tennessee, Virginia, New York, Oklahoma |
| 8a | 10 to 15°F (-12 to -9°C) | 3,430 | North Carolina, Georgia, Arkansas, Texas |
| 8b | 15 to 20°F (-9 to -7°C) | 3,379 | Texas, Alabama, Georgia, Mississippi |
| 9a | 20 to 25°F (-7 to -4°C) | 2,199 | Texas, Louisiana, Florida, California |
| 9b | 25 to 30°F (-4 to -1°C) | 2,085 | California, Texas, Florida, Arizona |
| 10a | 30 to 35°F (-1 to 2°C) | 1,234 | California, Florida, Texas, Arizona |
| 10b | 35 to 40°F (2 to 4°C) | 752 | California, Florida, Texas, Hawaii |
| 11a | 40 to 45°F (4 to 7°C) | 205 | Florida, California, Hawaii |
| 11b | 45 to 50°F (7 to 10°C) | 16 | Florida, Hawaii |
| 12a | 50 to 55°F (10 to 13°C) | 30 | Hawaii |
| 12b | 55 to 60°F (13 to 16°C) | 137 | Hawaii |
| 13a | 60 to 65°F (16 to 18°C) | 102 | Hawaii |
| 13b | 65 to 70°F (18 to 21°C) | 26 |
Zones come from the 2023 USDA Plant Hardiness Zone Map ZIP code listings published by the PRISM Climate Group at Oregon State University. Find yours with the zone finder, or read how the map works.