Not updated since its last revision in 2012, on November 15, the USDA ARS and partner PRISM Climate Group partners at Oregon State University released the much-anticipated 2023 update to the USDA Plant Hardiness Zone Map. The changes reflect a shift to warmer average annual extreme minimum temperatures during the most recent 30-year past period. As in previous versions, the 26 recognized Plant Hardiness Zonal divisions are presented with set temperature ranges based upon F-degree (F) half-zones, which can be searched by Zip Code. When planning for plant selection, growers are encouraged to remember that microclimate (small-scale) effects occur that can affect success of plants selected to be hardy within any given zonal range distribution.

The new map designations for the US, plus Alaska, Hawaii, and Puerto Rico, can be found at https://planthardiness.ars.usda.gov/, along with Tips For Growers and guidance about using the online map resources and its “on demand” layers.