USDA Plant Hardiness Zone Lookup – By Zip Code & Country

The USDA Plant Hardiness Zone Map divides North America into 13 zones based on the average annual minimum winter temperature. Each zone is further split into “a” and “b” half‑zones (5°F difference). This helps gardeners determine which plants are most likely to thrive in their location.

ZIP codes provide a precise and quick way to retrieve your exact zone without manually interpreting the color-coded map. It’s especially handy if you’re gardening in urban or micro‑climate areas where the general regional map may be ambiguous.

We use the official USDA hardiness zone data combined with geographic ZIP code mapping. The results reflect the most recent 2012 USDA map, which provides a reliable starting point for plant selection. Always consider local micro‑climates and soil conditions for best results.

Each numbered zone is subdivided into “a” (colder) and “b” (warmer) segments, representing a 5°F difference in average extreme minimum temperature. For example, Zone 7a means minimum temperatures between 0°F and 5°F, while Zone 7b means 5°F to 10°F.

Currently the lookup supports US ZIP codes only. We plan to add Canadian and UK postcode lookups in future updates. In the meantime, international gardeners can refer to global hardiness zone analogues published by various horticultural societies.

The most recent full map was released in 2012. The USDA occasionally publishes updates to reflect long-term climate trends, but currently the 2012 version remains the standard for plant hardiness in the United States.