For the first time in over a decade, the USDA updated its plant hardiness zone map. Used by gardeners, nurseries and research teams alike, this map divides the United States and Puerto Rico into 13 zones based on the lowest temperature areas experienced each year (or the “average annual extreme minimum temperature”). These zones are then divided in half for further localization.

While many zones did see an increase in average temperature, the most significant difference between the 2023 map and the 2012 version is the amount of data leveraged to create them. In 2012, 7,983 weather stations contributed. This year, more than 5,000 additional stations contributed to a more accurate look at regional zones.

In addition to helping plan gardens and nursery offerings, the plant hardiness zone map is used by the USDA Risk Management Agency to decide some crop insurance standards. Read more on the new USDA Plant Hardiness Zone Map here.