USDA Plant Hardiness Zone Map - Cooperative Extension: Garden and Yard - University of Maine Cooperative Extension

Image source: https://planthardiness.ars.usda.gov/ Interpreting the Plant Hardiness Zone Map How does this Hardiness Zone Map differ from the old one? This map is based on 30 years of weather data, from 1976-2005. The previous map was based on data from 1974-1986. Maine’s temperatures now appear slightly warmer. Part of this “warming” may be a result