Western Fence Lizard

here is one how looks like yours http://www.projectnoah.org/spottings/7562404

Because there are different species that look like one another we also need to check the natural geographical range of the species that looks like the spotting species. In this case Laudakia stellio is a species of agamid lizard found in Greece, Turkey, southwest Asia, and northeast Africa (http://reptile-database.reptarium.cz/species?genus=Laudakia&species=stellio). It also does not appear on this list of introduced lizards: http://www.californiaherps.com/info/introducedspecies.html. So I think it's not possible that this is the spotting from California, USA.

http://en.wikipedia.org/wiki/Laudakia_stellio Laudakia stellio I have one in my terrarium, it lokks very similar to your foto.

Sceloporus sp.?