The reason I bring this up is over the last couple months or so, that question was asked by a blog writer. I don't recall who or why the subject came up, but I can imagine that some people along the line have said that California is not part of the Southwest.
First, being the foremost, is the geographic location. Some people think that California looks like this on a map of the U.S.:
No matter how you look at it, California just doesn't fit in, but we'll see as the discussion progresses. Next up, the Climate.