Long Beach, CA. Very nice cycling community in town with two clubs and lots of cyclists on the roads almost daily. But really you can't go wrong anywhere along the Southern California coast. Many clubs, if you are into racing there are plenty around, if you ride centuries you can find a few every month. Weather here allows you to ride pretty much year round, no need to get a rain bike or serious winter gear, arm and leg warmers are pretty much it in winter and summers are not outrageously hot and humid.