A hardiness zone is a geographic area with a similar average minimum temperature. The map is based on the average annual extreme minimum temperature, so people in those areas know which plants can ...

Zones 1-6 are the coldest, and 7-13 the warmest. Zone 1 averages -60 degrees F while zone 13 never drops below 70 degrees F.

The USDA Plant Hardiness Zone Map consists of 13 individual zones that take in all of the contiguous United States, plus Alaska, Hawaii, and Puerto Rico. The first zone lies at the coldest and ...