In harsher climates than here, a north facing back yard works well. In the summer the sun tends to travel directly overhead, and if you have a good roof with good insulation, it will help to keep your house cooler. In the winter, the sun is much lower on the southern horizon and will hit the front of the house helping to warm it. I grew up in west Texas, and it makes a HUGE difference. In San Diego, there is also the coastal breeze to think about (if you’re in a location to take advantage), but it may be a wash with the sunlight in the afternoon.