Gardening zones help gardeners and farmers determine which plants grow best in a particular area based on that area's yearly precipitation and average low temperatures in the winter. Most commonly viewed as a color coded map, zones often correspond with information on seed packets or tags on plants.
The USDA originally released its complete garden zone map in 1965, including updated weather information from Florida. Over the years climate change has caused variances to the original map, prompting the USDA to release an updated and expanded map in 2012. This map adds two previously non-existent zones, although the USDA did not definitively admit that this change occurred due to global warming.