Plant Hardiness Zone Calculator

Your USDA Plant Hardiness Zone is the single most useful number for deciding what will survive winter in your garden, and this tool shows what a zone means once you pick it. The zone reflects the average annual minimum winter temperature, which sets the floor for which perennials, shrubs, and trees can make it through the cold months in your area. The current USDA map is the 2023 edition, released in November 2023 and built from 1991–2020 weather-station data; it replaced the 2012 map.

The temperature bands follow the official USDA Plant Hardiness Zone Map, built on the average annual extreme minimum winter temperature and sliced into 10-degree Fahrenheit zones. Each zone splits further into 'a' and 'b' subzones that represent 5-degree Fahrenheit increments. The calculator does not look up an address: find your zone with the ZIP code search on the USDA map site, then pick the whole-number zone (3 to 11) here. It returns that zone's 10-degree band plus example plants, a typical planting season and a winter-protection tip from its own built-in table, which is not a USDA list.

One zone can still contain pockets that behave differently, since elevation, nearby water, or urban heat islands all create microclimates worth watching on the ground. The zone speaks only to winter cold survival; it says nothing about summer heat, soil type, or rainfall, all of which matter just as much for healthy plants. Pushing a 'zone 5' plant into a 'zone 4' garden and expecting it to pull through without serious winter protection is the kind of mismatch that ends in dead stock.