Hardiness Zones 101 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 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 ...

SOURCE: United States Department of Agriculture Arkansas Democrat-Gazette Map showing Current plant hardiness zones in the U.S. and 1990 plant hardiness zones ...

Madison, Wisconsin, is projected to switch zones as the average coldest temperature is expected to increase by 8.4 degrees Fahrenheit.

The zones range from 3 to 11, starting with the lower numbers in the colder Northern states and the higher numbers in the milder Southern states. Louisiana includes just two zones, 8 and 9.

Zones are divided into 10-degree Fahrenheit increments from the coldest, with the lowest numbers increasing numerically with increased minimum temperatures. Zones are further subdivided into 5 ...

The U.S. government has updated its map of plant hardiness zones for the first time in more than a decade. The map sets out the average annual extreme minimum winter temperature across the country ...

“The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States,” said Kim Kaplan of the USDA’s Agricultural Research Service.

These zones were first put forth by the United States Department of Agriculture (USDA) in 1960 in response to a need to standardize growing zones with some measure of accuracy.