Hardiness Zone by ZIP Code
Find your USDA plant hardiness zone from the official 2023 map, plus your local frost dates, in one lookup. Covers 40,502 ZIP codes in all 50 states and Puerto Rico.
Your hardiness zone is set by the coldest night of an average winter where you live. The 2023 USDA map runs from zone 1a (below −55°F, interior Alaska) to 13b (above 65°F, Puerto Rico). Zone 6b covers the most U.S. ZIP codes (13%). Choose perennials rated for your zone or colder, and use frost dates, not zones, to time vegetable planting.
USDA hardiness zone temperature chart
Average annual extreme minimum temperature for each zone, with how many U.S. ZIP codes fall in it on the 2023 map.
| Zone | Coldest night (°F) | Coldest night (°C) | U.S. ZIP codes |
|---|---|---|---|
| 1a | −60°F to −55°F | −51°C to −48°C | 5 (<1%) |
| 1b | −55°F to −50°F | −48°C to −46°C | 11 (<1%) |
| 2a | −50°F to −45°F | −46°C to −43°C | 27 (<1%) |
| 2b | −45°F to −40°F | −43°C to −40°C | 17 (<1%) |
| 3a | −40°F to −35°F | −40°C to −37°C | 23 (<1%) |
| 3b | −35°F to −30°F | −37°C to −34°C | 230 (<1%) |
| 4a | −30°F to −25°F | −34°C to −32°C | 814 (2%) |
| 4b | −25°F to −20°F | −32°C to −29°C | 1,284 (3%) |
| 5a | −20°F to −15°F | −29°C to −26°C | 2,426 (6%) |
| 5b | −15°F to −10°F | −26°C to −23°C | 2,880 (7%) |
| 6a | −10°F to −5°F | −23°C to −21°C | 5,187 (13%) |
| 6b | −5°F to 0°F | −21°C to −18°C | 5,271 (13%) |
| 7a | 0°F to 5°F | −18°C to −15°C | 4,877 (12%) |
| 7b | 5°F to 10°F | −15°C to −12°C | 3,855 (10%) |
| 8a | 10°F to 15°F | −12°C to −9°C | 3,430 (8%) |
| 8b | 15°F to 20°F | −9°C to −7°C | 3,379 (8%) |
| 9a | 20°F to 25°F | −7°C to −4°C | 2,199 (5%) |
| 9b | 25°F to 30°F | −4°C to −1°C | 2,085 (5%) |
| 10a | 30°F to 35°F | −1°C to 2°C | 1,234 (3%) |
| 10b | 35°F to 40°F | 2°C to 4°C | 752 (2%) |
| 11a | 40°F to 45°F | 4°C to 7°C | 205 (<1%) |
| 11b | 45°F to 50°F | 7°C to 10°C | 16 (<1%) |
| 12a | 50°F to 55°F | 10°C to 13°C | 30 (<1%) |
| 12b | 55°F to 60°F | 13°C to 16°C | 137 (<1%) |
| 13a | 60°F to 65°F | 16°C to 18°C | 102 (<1%) |
| 13b | 65°F to 70°F | 18°C to 21°C | 26 (<1%) |
Hardiness zones by state
The range of zones in each state and the zone that covers the most ZIP codes. Open a state for town-by-town zones and frost dates.
| Alabama | 7b–9b | 8b | 804 |
| Alaska | 1a–8b | 5a | 272 |
| Arizona | 5b–10a | 9b | 522 |
| Arkansas | 7a–8b | 8a | 694 |
| California | 5b–11a | 9b | 2,554 |
| Colorado | 4a–7a | 6a | 625 |
| Connecticut | 6a–7b | 6b | 419 |
| Delaware | 7a–8a | 7b | 93 |
| District of Columbia | 7b–8a | 8a | 289 |
| Florida | 8b–11b | 10a | 1,454 |
| Georgia | 7a–9a | 8a | 937 |
| Hawaii | 10b–13a | 12b | 133 |
| Idaho | 4a–7b | 6b | 313 |
| Illinois | 5a–7a | 6a | 1,545 |
| Indiana | 5b–7a | 6a | 929 |
| Iowa | 4b–6a | 5a | 1,042 |
| Kansas | 6a–7a | 6b | 741 |
| Kentucky | 6b–7b | 7a | 933 |
| Louisiana | 8b–10a | 9a | 710 |
| Maine | 3b–7a | 5a | 478 |
| Maryland | 6a–8a | 7b | 598 |
| Massachusetts | 5b–7b | 6b | 675 |
| Michigan | 4a–7a | 6a | 1,154 |
| Minnesota | 3a–5a | 4b | 943 |
| Mississippi | 7b–9a | 8b | 524 |
| Missouri | 5b–8a | 6b | 1,144 |
| Montana | 3b–6b | 4b | 399 |
| Nebraska | 5a–6a | 5b | 609 |
| Nevada | 5a–10a | 9b | 250 |
| New Hampshire | 4a–6b | 6a | 280 |
| New Jersey | 6b–8a | 7a | 715 |
| New Mexico | 5a–8b | 7b | 419 |
| New York | 4a–7b | 6a | 2,125 |
| North Carolina | 6b–9a | 8a | 1,072 |
| North Dakota | 3b–4b | 4a | 405 |
| Ohio | 6a–7a | 6b | 1,391 |
| Oklahoma | 6b–8a | 7b | 761 |
| Oregon | 5b–9b | 8b | 473 |
| Pennsylvania | 5b–8a | 6b | 2,108 |
| Rhode Island | 6b–7b | 7a | 88 |
| South Carolina | 8a–9b | 8b | 526 |
| South Dakota | 4a–5b | 4b | 382 |
| Tennessee | 6b–8a | 7b | 774 |
| Texas | 6b–10b | 8b | 2,571 |
| Utah | 4a–8b | 6a | 337 |
| Vermont | 4a–6a | 5a | 305 |
| Virginia | 6a–8b | 7b | 1,196 |
| Washington | 6a–9b | 8b | 708 |
| West Virginia | 5b–7a | 7a | 843 |
| Wisconsin | 3b–6a | 5b | 872 |
| Wyoming | 4a–5b | 5a | 191 |
| Puerto Rico | 11b–13b | 13a | 176 |
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
- Puerto Rico
Frequently asked questions
What is a plant hardiness zone?
A USDA plant hardiness zone is based on the average annual extreme minimum temperature: the coldest night of a typical winter. Each zone is a 10°F band split into "a" (colder) and "b" (warmer) halves of 5°F. Plants labeled for your zone or a lower number should survive your winters.
How do I find my hardiness zone?
Enter your 5-digit ZIP code in the zone finder above. It looks up your zone in the official USDA 2023 ZIP code files and shows the temperature range, the zone in degrees Celsius and your local frost dates.
Did the hardiness zone map change in 2023?
Yes. The USDA released a new map in November 2023 based on 1991–2020 temperatures. About half of the country moved half a zone warmer than on the 2012 map, so plant tags and older books may show an outdated zone for you.
Is my hardiness zone the same as my planting zone?
People often use the terms interchangeably, but hardiness zones only measure winter cold. They don't tell you when to plant vegetables. For that, use your average last spring and first fall frost dates.
What is the difference between zone 6a and 6b?
Zone 6b is 5°F warmer than zone 6a. In 6a the coldest winter night averages −10°F to −5°F; in 6b it averages −5°F to 0°F. The same rule applies to every "a" and "b" pair.
Related free tools
Frost Dates by ZIP
Last and first frost from the nearest NOAA station.
Open tool →Acreage Calculator
Draw your lot on a satellite map, or enter sides, for acres and square feet.
Open tool →Square Feet to Acres Calculator
Convert sq ft, acres, hectares, m², sq yd and sq mi.
Open tool →Raised Bed Soil Calculator
Soil and mix ingredients for raised beds, in cu ft, yards and bags.
Open tool →Sources
USDA Agricultural Research Service, 2023 Plant Hardiness Zone Map; ZIP code zone files from the PRISM Climate Group, Oregon State University. Frost dates: NOAA NCEI 1991–2020 U.S. Climate Normals. This is an independent tool, not an official USDA site. How the lookup works.