The USDA's 2023 plant hardiness zone introduces two new zones (12 and 13) to account for hotter weather, and it harnesses better GIS technology to delineate warmer urban areas, cooler elevated areas and even warmer areas downwind from large bodies of water.
all in all they used 13,625 weather reporting stations to create the map. it's the first update since 2012 and utilizes 30 years of data.
