In 2012, The U.S. Department of Agriculture released the most current version of its Plant Hardiness Zone Map (PHZM). The map is based on the average low temperature in the winter time. Growers across the country use plant hardiness zones to help determine when to plant and which plants will be most appropriate for their area. The best location to peruse this map is probably on the USDA website where they have an interactive version.
Plant hardiness is an important consideration, but remember to also consider light, soil moisture, soil composition, summer temperatures, humidity and other concerns.