What does this growing zone lookup show?
This lookup returns the USDA Plant Hardiness Zone associated with your ZIP code, along with the listed city and state. The zone is based on the average annual extreme minimum winter temperature for a 30-year climate period. It is most useful when you are checking whether a perennial plant is likely to survive the coldest part of winter in your area.
The lookup is a location reference, not a complete growing guide. Your garden may be warmer or colder than the ZIP code average because of elevation, slope, buildings, pavement, exposure, and cold-air drainage.
How to use your USDA hardiness zone
Use the zone on a plant label or in a perennial growing guide as a winter-survival filter. If a plant is listed for zones 5 to 8 and your result is zone 6b, the plant is within its listed hardiness range. That does not guarantee success. Drainage, summer heat, soil moisture, sunlight, pests, and the plant's age at planting still matter.
A zone is especially useful for trees, shrubs, bulbs, and herbaceous perennials that must survive more than one season. Annual vegetables often finish before winter, so their planting dates depend more on soil temperature, day length, crop maturity, and local freeze dates.
What hardiness zones do not measure
A USDA zone does not tell you the date of your last spring freeze or first fall freeze. Two places with the same zone can have different growing-season lengths. It also does not measure summer heat, rainfall, humidity, soil type, wind, snow cover, or the amount of sun in your garden.
For example, a zone can help you decide whether a rosemary variety might survive winter, but it cannot tell you when to transplant tomatoes. Use the frost date finder for freeze probabilities and the planting calendar for crop timing.
How the zone is calculated
The USDA Plant Hardiness Zone Map divides areas into 10-degree Fahrenheit zones based on the average annual extreme minimum temperature. Each zone is split into two 5-degree subzones, written with an a or b. The lower letter is colder. A 6a location has a colder average winter minimum than a 6b location.
This lookup uses the 2023 USDA Plant Hardiness Zone ZIP code data published by the PRISM Climate Group at Oregon State University. The map describes a climate average, not the coldest temperature that will ever occur at your address.
Practical examples
Choosing a perennial
A gardener in zone 7b can use the zone to screen out perennials rated only for colder zones, then compare the plant's light, moisture, and soil requirements with the garden. The zone narrows the list, but it does not choose the plant by itself.
Planning vegetables
A gardener in zone 6b can still have a different spring planting date from another zone 6b garden. The frost date finder uses the nearest eligible NOAA station and shows the station distance, while the planting calendar turns the median spring freeze into crop windows.
Checking a microclimate
A sheltered courtyard beside a south-facing wall may stay warmer than the surrounding ZIP code. A low garden at the bottom of a slope may collect cold air. If your experience differs from the lookup, use local observations and current forecasts alongside the zone result.
Where our data comes from
USDA hardiness zones come from the 2023 Plant Hardiness Zone ZIP Code Listings published by the PRISM Climate Group at Oregon State University. The underlying zone method uses average annual extreme minimum temperatures from 1991 to 2020. ZIP place names and coordinates come from GeoNames postal data. We do not send your ZIP code to a third-party lookup service at runtime.
The map vintage matters. USDA may publish a later map or revised ZIP listings in the future, so the result includes the data vintage used by this tool.
Frequently asked questions
Is a hardiness zone the same as a growing zone?
In gardening, "growing zone" commonly means USDA Plant Hardiness Zone. The official term is hardiness zone because it describes winter survival, especially for perennial plants. It does not describe every condition that affects growth.
Can a ZIP code have more than one zone?
Yes. ZIP codes can cover a broad area, and local elevation or exposure can differ within the same postal area. This lookup returns the zone assigned to the ZIP code record, so treat it as a useful regional estimate rather than a measurement from your garden.
Should I use my zone to choose vegetable planting dates?
Use the zone as background context, but use freeze dates and crop-specific guidance for planting dates. The frost date finder shows spring and fall freeze probabilities, and the planting calendar uses those dates to build crop windows.
