New Plant Zone Hardiness Maps

The USDA released a new plant cold hardiness zone map on November 15, 2023. This new map is based on the annual, average, winter temperature. It is not the coldest temperature reached in winter, but rather is an average based on 30 years-worth of data. This map, updated from 2012, has more accurate, detailed information as the number of weather stations suppling the data increased by 68%.

The importance of this map's information is to help gardeners select cold hardy woody and herbaceous plants for their area. The zones are divided into 10°F increments. Lower zone numbers are colder climates, higher numbers represent warmer climates.

To view the map and learn more visit: https://hort.extension.wisc.edu/articles/maps/