The USDA has announced the availability of a new GIS-based plant hardiness zone map, which is zoomable and is based on 1976-2005 data. You can read more about it at https://planthardiness.ars.usda.gov/PHZMWeb/AboutWhatsNew.aspx. You can access the map at the link above by clicking on Interactive Map on the top menu or go directly to it at https://planthardiness.ars.usda.gov/PHZMWeb/InteractiveMap.aspx.