The numbers used in the climate zone map don't have a title or legend. The California climate zones shown in this map are not the same as what we commonly call climate areas such as "desert" or "alpine" climates. The climate zones are based on energy use, temperature, weather and other factors.
This is explained in the Title 24 energy efficiency standards glossary section: "The Energy Commission established 16 climate zones that represent a geographic area for which an energy budget is established. These energy budgets are the basis for the standards...." "(An) energy budget is the maximum amount of energy that a building, or portion of a building...can be designed to consume per year." "The Energy Commission originally developed weather data for each climate zone by using unmodified (but error-screened) data for a representative city and weather year (representative months from various years). The Energy Commission analyzed weather data from weather stations selected for (1) reliability of data, (2) currency of data, (3) proximity to population centers, and (4) non-duplication of stations within a climate zone. "Using this information, they created representative temperature data for each zone. The remainder of the weather data for each zone is still that of the representative city." The representative city for each climate zone (CZ) is: CZ 1: Arcata CZ 2: Santa Rosa CZ 3: Oakland CZ 4: San Jose-Reid CZ 5: Santa Maria CZ 6: Torrance CZ 7: San Diego-Lindbergh CZ 8: Fullerton CZ 9: Burbank-Glendale CZ10: Riverside CZ11: Red Bluff CZ12: Sacramento CZ13: Fresno CZ14: Palmdale CZ15: Palm Spring-Intl CZ16: Blue Canyon
For more information regarding the climate zone map, please contact the Title 24 Energy Efficiency Standards Hotline at: E-mail: title24@energy.ca.gov 916-654-5106  800-772-3300 (toll free in California)