Plant Hardiness Zones 2024 Map. Recently, the usda updated its plant hardiness map for the first time in 11 years. The plant hardiness zone map was updated for the 2024 gardening season with the addition of thousands more local weather stations.
These zones are delineated based on the average annual lowest minimum temperature. The usda plant hardiness zone map (phzm) is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location.