USDA Plant Hardiness Zone Guide
The USDA Plant Hardiness Zone Map is the standard reference for gardeners and growers across the United States. It divides North America into 13 primary zones based on the average annual extreme minimum winter temperature, with each zone further divided into "a" (colder half) and "b" (warmer half) subzones. The map was most recently updated in 2023, and about half of the country shifted to a warmer zone compared to the previous 2012 edition, reflecting observed warming trends in minimum winter temperatures.
All USDA Hardiness Zones
The table below lists all 26 USDA hardiness subzones from the coldest (1a, at negative 60 degrees Fahrenheit) to the warmest (13b, at 65 to 70 degrees Fahrenheit). Each zone spans a 5-degree Fahrenheit range of average annual extreme minimum winter temperature. Click a zone number for detailed planting recommendations and a list of cities in that zone.
| Zone | Min Temp (°F) | Max Temp (°F) | Description | Details |
|---|---|---|---|---|
| 1a | -60°F | -55°F | Extreme arctic conditions; only the hardiest perennials survive | Zone 1 guide |
| 1b | -55°F | -50°F | Interior Alaska; very limited plant selection | Zone 1 guide |
| 2a | -50°F | -45°F | Northern Alaska and mountain peaks; short growing season | Zone 2 guide |
| 2b | -45°F | -40°F | Interior Alaska and northern plains; cold-hardy trees and shrubs | Zone 2 guide |
| 3a | -40°F | -35°F | Northern Minnesota, Montana; apples, lilacs, and hardy roses | Zone 3 guide |
| 3b | -35°F | -30°F | Northern Great Plains; expanded perennial options | Zone 3 guide |
| 4a | -30°F | -25°F | Northern Midwest and New England; most fruit trees thrive | Zone 4 guide |
| 4b | -25°F | -20°F | Central Midwest and mountain valleys; wide vegetable gardening | Zone 4 guide |
| 5a | -20°F | -15°F | Central states and mid-Atlantic; popular gardening zone | Zone 5 guide |
| 5b | -15°F | -10°F | Lower Midwest and coastal New England; diverse plant palette | Zone 5 guide |
| 6a | -10°F | -5°F | Mid-Atlantic and central Oregon; moderate winter cold | Zone 6 guide |
| 6b | -5°F | 0°F | Pacific Northwest coast and upper South; extended season | Zone 6 guide |
| 7a | 0°F | 5°F | Upper South and coastal Pacific Northwest; mild winters | Zone 7 guide |
| 7b | 5°F | 10°F | Central South and mid-Atlantic coast; long growing season | Zone 7 guide |
| 8a | 10°F | 15°F | Deep South and Pacific coast; camellias and gardenias thrive | Zone 8 guide |
| 8b | 15°F | 20°F | Gulf Coast and Southern California; subtropical plants | Zone 8 guide |
| 9a | 20°F | 25°F | Florida and desert Southwest; citrus grows well | Zone 9 guide |
| 9b | 25°F | 30°F | Southern Florida and coastal California; near-tropical | Zone 9 guide |
| 10a | 30°F | 35°F | South Florida and Southern California; tropical plants | Zone 10 guide |
| 10b | 35°F | 40°F | Miami and coastal SoCal; frost-free most years | Zone 10 guide |
| 11a | 40°F | 45°F | Hawaii and Key West; year-round tropical gardening | Zone 11 guide |
| 11b | 45°F | 50°F | Tropical Hawaii; no frost risk | Zone 11 guide |
| 12a | 50°F | 55°F | Tropical Pacific islands; fully tropical climate | Zone 12 guide |
| 12b | 55°F | 60°F | Equatorial regions; constant warmth year-round | Zone 12 guide |
| 13a | 60°F | 65°F | Equatorial lowlands; perpetual summer conditions | Zone 13 guide |
| 13b | 65°F | 70°F | True tropics; no seasonal temperature variation | Zone 13 guide |
How to Use Hardiness Zones
Hardiness zones serve as a starting point for selecting plants that can survive winter in your area. When shopping for perennial plants, trees, and shrubs, look for the hardiness zone rating on the plant tag or catalog listing. A plant rated for zone 5 can survive minimum temperatures of negative 20 to negative 10 degrees Fahrenheit and will also grow in any warmer zone (6 through 13). However, some plants also have a maximum zone tolerance: lilacs, for example, need sufficient winter chill and may not thrive in zones warmer than 8.
Keep in mind that hardiness zones only measure one variable: extreme minimum winter temperature. They do not account for summer heat, humidity, rainfall, soil type, wind exposure, or the length of your growing season. Two locations in the same hardiness zone can have dramatically different gardening conditions. Phoenix (zone 9b) and Jacksonville (zone 9a) are in similar zones, but their gardening calendars, rainfall patterns, and suitable crops differ enormously. That is why combining your hardiness zone with your local frost dates and growing season data provides the most complete picture for garden planning.
Zone Ratings on Plant Labels
A plant labeled "Hardy to Zone 5" means it can survive winter temperatures down to negative 20 degrees Fahrenheit. It will grow in zone 5 and all warmer zones (6 through 13). If your zone number is lower (colder) than the plant's rating, it will likely need winter protection or should be grown as an annual.
Microclimates Matter
Your garden may contain microclimates that are warmer or cooler than the zone assigned to your area. South-facing walls, sheltered courtyards, and areas above frost-draining slopes can be a half-zone warmer than exposed open ground. Low-lying areas where cold air pools can be a full zone colder than surrounding higher ground.
Zone Groups at a Glance
Click any zone group below for detailed planting recommendations, frost protection tips, and a list of cities in that zone range.
-60 to -50°F
Extreme arctic conditions; only the hardiest perennials survive Zone 2
-50 to -40°F
Northern Alaska and mountain peaks; short growing season Zone 3
-40 to -30°F
Northern Minnesota, Montana; apples, lilacs, and hardy roses Zone 4
-30 to -20°F
Northern Midwest and New England; most fruit trees thrive Zone 5
-20 to -10°F
Central states and mid-Atlantic; popular gardening zone Zone 6
-10 to 0°F
Mid-Atlantic and central Oregon; moderate winter cold Zone 7
0 to 10°F
Upper South and coastal Pacific Northwest; mild winters Zone 8
10 to 20°F
Deep South and Pacific coast; camellias and gardenias thrive Zone 9
20 to 30°F
Florida and desert Southwest; citrus grows well Zone 10
30 to 40°F
South Florida and Southern California; tropical plants Zone 11
40 to 50°F
Hawaii and Key West; year-round tropical gardening Zone 12
50 to 60°F
Tropical Pacific islands; fully tropical climate Zone 13
60 to 70°F
Equatorial lowlands; perpetual summer conditions
The 2023 USDA Zone Map Update
The USDA released an updated hardiness zone map in November 2023, incorporating 30 years of temperature data from 1991 to 2020. The new map shifted approximately half of the country into a warmer zone compared to the 2012 map. This means many gardeners can now grow plants previously considered marginal for their area. However, the shift reflects averages and does not eliminate the risk of occasional extreme cold events. Polar vortex disruptions and other weather anomalies can still bring temperatures well below your zone's average minimum. Gardeners in transitional areas should continue to factor in worst-case scenarios when selecting expensive perennial investments like fruit trees and ornamental specimens.
If you are unsure which zone you fall in, enter your ZIP code on the official USDA Plant Hardiness Zone Map for the most precise determination. Our city-level data provides a good approximation for the representative cities listed, but microclimates and elevation differences within a city can result in zone variations.
Hardiness Zones vs. Frost Dates
Gardeners sometimes confuse hardiness zones with frost dates, but they measure different things and serve different purposes. Your hardiness zone tells you the coldest temperature your location typically experiences during winter, which determines whether perennial plants can survive dormancy. Your frost dates tell you when the growing season begins and ends, which matters for annual vegetable and flower gardening. A location in zone 6b might have a last spring frost in late April or mid-May depending on latitude, elevation, and local climate factors. Both pieces of information are needed for comprehensive garden planning.
Use our frost date calculator to find the specific frost dates and growing season for your city.