What does my hardiness zone mean?

It is the average coldest night of the year where you live, in 10°F bands (a and b are 5°F halves), averaged over 1991–2020 for the 2023 USDA map. A plant rated for your zone should survive a normal winter.

Did my zone change in 2023?

Many places moved half a zone warmer when the USDA map was updated in 2023 with newer temperature data. This tool uses the 2023 map.

Why did a plant rated for my zone die?

Zones only describe winter cold. Summer heat, humidity, drought and wet winter soil kill many plants that are perfectly hardy. Our lists also check your region's summers.

Are the frost dates exact?

No. They are typical dates for the zone and can be off by two weeks or more where you live. Check with a local nursery or extension office.

Free tool · Hardiness zone by ZIP

What's my hardiness zone?

Find your 2023 USDA hardiness zone from your ZIP code, with typical frost dates, planting windows and what your zone does not tell you about summer heat.

How it works

Your ZIP is looked up in the 2023 USDA Plant Hardiness Zone Map's ZIP file (each ZIP gets the zone at its centre). A zone is the average coldest night of the year, 1991–2020, in 10°F bands; "a" is the colder half and "b" the warmer.

Frost dates and planting windows are typical values for the whole zone, so treat them as a starting point. The zone says nothing about summer heat, humidity or rainfall, which is why we also tell you what your region's summers are like.

Worked example

ZIP 30303 (downtown Atlanta) is zone 8a: the coldest night of an average winter is 10°F to 15°F. Spring planting runs from after the last frost (typically late March in Atlanta) to early May. But Atlanta's long, humid summers rule out many plants that are hardy in zone 8, such as northern shrubs. See what to plant in Atlanta, Georgia.

Data sources

USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture. Data by the PRISM Climate Group, Oregon State University.
ZIP code to state data: GeoNames (geonames.org), licensed under CC BY 4.0.

Plant lists by condition

Sample beds of 12 × 6 ft with quantities worked out the same way as this tool.

All plant guides

Questions and answers

What does my hardiness zone mean?: It is the average coldest night of the year where you live, in 10°F bands (a and b are 5°F halves), averaged over 1991–2020 for the 2023 USDA map. A plant rated for your zone should survive a normal winter.
Did my zone change in 2023?: Many places moved half a zone warmer when the USDA map was updated in 2023 with newer temperature data. This tool uses the 2023 map.
Why did a plant rated for my zone die?: Zones only describe winter cold. Summer heat, humidity, drought and wet winter soil kill many plants that are perfectly hardy. Our lists also check your region's summers.
Are the frost dates exact?: No. They are typical dates for the zone and can be off by two weeks or more where you live. Check with a local nursery or extension office.