It’s almost always foggy until mid-afternoon when it finally clears away.

Yes, it was foggy, but I can’t imagine that would be the cause for the crash given SoCal pilots deal with that nearly every day. Not to mention all the instruments on board to help the pilot identify their altitude. If they clipped a mountain I don’t believe it would’ve solely been because of fog, and possibly due to intentionally wanting to be that low to see something on the ground.