I live in the midwest right now, and whenever I contemplate moving to the west coast, one of the things I would dislike the most is giving up having 4 distinct seasons.
The first warm days of spring, crisp fall mornings, "its so hot out we have to go swimming at the lake" days in summer, and the first snow of the year - these are just a few things that, in moderation, are really enjoyable to me (and many others).