You got it fairly close. The coast is always cooler The cool breeze off the ocean can make its way up a few of the valleys and keep things nice some 15 to 20 miles inland. A few of those valleys Don't get much of the ocean breeze and are bowls smoldering in the sun all day. Most of the valley's are high density areas which are nothing but concrete, asphalt, and stucco. They make for a Giant heat sinks and man o man does it get warm. The mountains are just east of us so the cooler coast air hits the hot desert air which is just on the other side of the mountains and develops into the big Thunder bumpers that often light up the eastern sky. Seldom do we get much moister from them but they are impressive to watch and listen to. This whole region is a desert.