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The growth and spread of plants is governed by the climate that they're growing in; the length of the season, the timing timing of and total accumulation of rainfall, winter low and summer high temperatures, wind, and humidity.

Unlike the familiar Hardiness Zone maps (devised by the US Department of Agriculture) which breaks North America into zones based entirely on winter low temperatures, Climate Zone maps factor the entire climate.

You will begin seeing Climate Zone maps shared along side the Hardiness Zone maps in our state listings starting Spring 2021.

Conversion of the USDA Zones to their Sunset Climate Zone Equivelance can be done through the below chart.

Hardiness Zone	Fahrenheit	Celsius	Sunset Zone
1	Below -50°F	Below -45.6°C	A1
2a	-50 to -45°F	-45.6 to -42.8°C	A1
2b	-45 to -40°F	-42.8 to -40°C	A1
3a	-40 to -35°F	-40 to -37.2°C	A1
3b	-35 to -30°F	-37.2 to -34.4°C	A1
4a	-30 to -25°F	-34.4 to -31.7°C	A1
4b	-25 to -20°F	-31.7 to -28.9°C	A1
5a	-20 to -15°F	-28.9 to -26.1°C	1A, 1B, A2
5b	-15 to -10°F	-26.1 to -23.3°C	1-2
6a	-10 to -5°F	-23.3 to -20.6°C	1-3
6b	-5 to 0°F	-20.6 to -17.8°C	1-3
7a	0 to 5°F	-17.8 to -15°C	6
7b	5 to 10°F	-15 to -12.2°C	6-7
8a	10 to 15°F	-12.2 to -9.4°C	4, 6-9
8b	15 to 20°F	-9.4 to -6.7°C	4-5, 7-9
9a	20 to 25°F	-6.7 to -3.9°C	16
9b	25 to 30°F	-3.9 to -1.1°C	16-22
10a	30 to 35°F	-1.1 to 1.7°C	17-23, 26
10b	35 to 40°F	1.7 to 4.4°C	23-24, 26
11	Above 40°F	Above 4.4°C	25, H1, H2