Why are California Arizona and Florida always sunny?

Answer 1

Southern California, Arizona, Nevada, and nearby areas tend to be under
the influence of of global scale high pressure. This feature is cased by
air that rose with tropical convection, was transported to the mid-latitudes,
then descends. As it descends, it becomes warm without getting any
wetter, so it will be free of clouds.

Florida is in an area that is much wetter. It's rather moist and occasionally
cloudy. It's warmer than the rest of the United States because it's
closer to the equator, so the sun is closer to vertical. It's also less
likely to get hit by the sort of cold air outbreaks that lead to cold
cloudy conditions typical of the middle of the country.