USDA Zone to Sunset Zone Conversion Table for California

USDA Zone

Av. Min. Temp. in F

Sunset Climatic Zone

6a

-10 to -5

1A, 2A, 2B, 3

6b

-5 to 0

1A,2A, 2B, 3

7a

0 to 5

6

7b

5 to 10

6, 7

8a

10 to 15

4, 6, 7, 8, 9

8b

15 to 20

4, 5, 7, 9

9a

20 to 25

16

9b

25 to 30

16, 17, 18, 19, 20, 21, 22

10a

30 to 35

17, 18, 19, 20, 21, 22, 23, 26

10b

35 to 40

23, 24, 26