use the facts that water has a higher specific heat than rock (such as Granite) to explain the differences in the temperature curves for the two cities in the graph.

Since water has a high specific heat, that results in water being able to store/require more energy in order to change it’s temperature. Since San Francisco is so close to water, that would mean that it’s temperature should vary less since water would be able to keep the temperature around the same value even if there was an increase or decrease in thermal energy.  

the answer is symmetrical : )