The USDA divides North America into 11 hardiness zones. Each zone represents an area of winter plant hardiness.
Zone 1 is the coldest, found in Canada and the far northern U.S.; zone 11 is the warmest, a tropical area that is essentially frost-free and found only in Hawaii and southernmost Florida.
The temperatures listed indicate the average annual minimum temperatures — the lowest temperatures that can be expected each year.
Zone 1 | Below -50 F (-45.6 C) |
Zone 2 | -50 to -40 F (-45.6 to -40 C) |
Zone 3 | -40 to -30 F (-40 to -34.5 C) |
Zone 4 | -30 to -20 F (-43.5 to -28.9 C) |
Zone 5 | -20 to -10 F (-28.9 to -23.3 C) |
Zone 6 | -10 to 0 F (-23.3 to -17.8 C) |
Zone 7 | 0 to 10 F (-17.8 to -12.3 C) |
Zone 8 | 10 to 20 F (-12.3 to -6.6 C) |
Zone 9 | 20 to 30 F (-6.6 to -1.1 C) |
Zone 10 | 30 to 40 F (-1.1 to 4.4 C) |
Zone 11 | 40 F and above (4 C and above) |
