
The lowest winter temperatures vary across the country, from Alaska to Florida, and some plants are better adapted to thrive in colder winter temperatures than others. To help make all this easy to understand, the United States Department of Agriculture (USDA) has collated records of the average coldest winter temperatures from all over the country.
This data has been plotted onto a map and the country divided into 13 zones which are displayed on the USDA Hardiness Zone map and numbered zone 1 (the coldest) to zone 13 (the warmest). The map reveals the hardiness zone in which you live.