The U.S. Department of Agriculture recently updated its Plant Hardiness Zone Map.
What’s a plant hardiness zone? It’s a zone based on the “average annual extreme minimum temperature during a 30-year period in the past” and helps gardeners determine whether a plant has a chance to thrive in that zone. The 2012 map is more finely tuned than past maps were. Still, don’t expect your town’s zones to apply everywhere in town. Every place has microclimates whose conditions are affected by water, pavement, sunlight, shade, and buildings.