What is a Plant Hardiness Zone?

The plant hardiness zone is a standard by which gardeners can determine which plants will thrive in their specific location based on weather data that is collected. Zone 1 is the coldest with zone 13 being the warmest.

USDA Plant Hardiness Zone Map 2023 covering the United States, Alaska, Hawaii, and Puerto Rico. Shows different climate zones based on average annual extreme minimum temperatures from 1991-2020, color-coded from blues (coldest) to reds (warmest).

Click on the link which will take you to an interactive map. You will be able to click on a dot to see the average date (1991-2020) that temperatures drop below freezing.

Table showing average last and first frost dates by agricultural hardiness zones in the United States, with zones 1 to 13 listed. Zone 1: last frost May 22-Jun 4, first frost Aug 25-31. Zone 13: no usual frost.