Find Your Zone
Finding your zone is one of the most important things you can do when you are choosing plants for your garden. The United States Department of Agriculture published the above map to illustrate where the various zones are. This map appears on their website in an interactive format that allows you to zoom in on your geographical area. It can be found by clicking the button below.
The zones are differentiated by the average minimum temperature and are widely used. There have been a few iterations of this map, updated every once in a while to compensate for climate change (the last update was done in 2023). In addition to the USDA hardiness zones, The company Sunset (which publishes gardening books and magazines) has also created a climate zone map. Their climate zones are more comprehensive, taking into account averages of maximum, minimum and mean temperatures, humidity, rainfall, and the length of the growing season (among other variables). Their extensive mapping system can be found here:
Below are two of the Sunset Zone Maps that cover the San Francisco Bay Area, as well as a conversion chart for translating from the USDA Hardiness Zones to their corresponding Sunset Zones. For the purposes of this course, we will be using the Sunset Zone system, as it is a more comprehensive system, especially for the western United States.
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Sunset Zone / USDA Hardiness Map Conversion Chart
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USDA Zone
1
2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11 |
Temperature (F)
below -50 F
-50 to -45 F -45 to -40 F -40 to -35 F -35 to -30 F -30 to -25 F -25 to -20 F -20 to -15 F -15 to -10 F -10 to -5 F -5 to 0 F 0 to 5 F 5 to 10 F 10 to 15 F 15 to 20 F 20 to 25 F 25 to 30 F 30 to 35 F 35 to 40 F above 40 F |
Sunset Zone
A1
A1 A1 A1 A1 A1 A1 1A, 1B, A2 1-2 1-3 1-3 6 6-7 4, 6-9 4-5, 7-9 16 16-22 17-23, 26 23-24, 26 25, H1, H2 |
