USDA hardiness zone finder
Find your plant hardiness zone by ZIP code from the official 2023 USDA map, or estimate it for any town in the world, and see which winters it’s built from.
How a hardiness zone is worked out
A hardiness zone is a single temperature: the average of the coldest night of each winter over 30 years. The USDA map uses 1991–2020. Zone 1 starts at −60°F, every zone spans 10°F, and each is split into an “a” and a “b” half 5°F apart.
That average hides a lot. Most winters are milder than your zone; roughly one in five or six is a full half zone colder. That is why nursery labels list a plant’s coldest safe zone, and why gardeners at the edge of a plant’s range protect it in a hard winter.
Zones are about survival, not timing. Seattle and Atlanta are both zone 8, but Seattle’s cool summers can’t ripen what Atlanta’s can. For sowing dates, use your last and first frost dates.
USDA hardiness zone temperature chart
| Zone | “a” half | “b” half | Celsius | Examples (2023 map) |
|---|---|---|---|---|
| 1 | -60 to -55°F | -55 to -50°F | -51 to -46°C | — |
| 2 | -50 to -45°F | -45 to -40°F | -46 to -40°C | — |
| 3 | -40 to -35°F | -35 to -30°F | -40 to -34°C | Northern Minnesota, North Dakota |
| 4 | -30 to -25°F | -25 to -20°F | -34 to -29°C | Minneapolis, much of Montana and Maine |
| 5 | -20 to -15°F | -15 to -10°F | -29 to -23°C | Chicago, Denver, Omaha |
| 6 | -10 to -5°F | -5 to 0°F | -23 to -18°C | Boston, St. Louis, Salt Lake City |
| 7 | 0 to 5°F | 5 to 10°F | -18 to -12°C | New York City, Nashville, Oklahoma City |
| 8 | 10 to 15°F | 15 to 20°F | -12 to -7°C | Atlanta, Dallas, Seattle |
| 9 | 20 to 25°F | 25 to 30°F | -7 to -1°C | Houston, Orlando, much of coastal California |
| 10 | 30 to 35°F | 35 to 40°F | -1 to 4°C | Miami, Los Angeles, San Diego |
| 11 | 40 to 45°F | 45 to 50°F | 4 to 10°C | Hawaii lowlands, Florida Keys |
| 12 | 50 to 55°F | 55 to 60°F | 10 to 16°C | Puerto Rico and Hawaii coasts |
| 13 | 60 to 65°F | 65 to 70°F | 16 to 21°C | Parts of Puerto Rico |
Questions gardeners ask
What zone am I in?
Enter your ZIP code above. US results come from the official 2023 USDA Plant Hardiness Zone Map (via the PRISM Climate Group data published with it). Outside the US, PlantWise estimates a USDA-equivalent zone from 30 years of recorded winter lows.
What changed in the 2023 USDA hardiness zone map?
The 2023 map uses 1991–2020 weather data instead of 1976–2005. About half of the US shifted into the next warmer half zone, and the rest stayed the same. The change reflects both a warmer period and many more weather stations.
Does my zone tell me when to plant?
No. Hardiness zones only describe how cold winter gets, so they tell you which perennials, shrubs and trees will survive. Planting dates for vegetables depend on your frost dates, which two places in the same zone can differ on by weeks.
What do the “a” and “b” in 7a and 7b mean?
Each zone spans 10°F of average extreme winter low and is split into two 5°F half zones. “a” is the colder half, “b” the warmer.
Can I grow plants rated for a warmer zone?
Sometimes, in a sheltered microclimate: against a south-facing wall, in a city, or with winter mulch. Containers are riskier than the ground because roots are exposed to air temperature.