[rrrrrrrrrrrryan]

Most older (pre-1980s) buildings in SoCal lack A/C. It all depends on how far you are from the coast, but the evenings in the summer are mostly tolerable with a fan and some open windows.

Nobody except masochists really stay inside a stuffy apartment mid-day in the summer though. The reason you pay so much in living expenses is mostly for the good weather, so people spend their weekends out and about. As a kid in the summer, I remember walking around shops in the mall just to stay cool during the hottest hours of the day, and going to the beach often. My parents would do their grocery store shopping on Saturdays and Sundays mid-day if it was going to be hot. As I got older we'd go catch a matinee, or hit up a restaurant or a bar.

I imagine workers in the L.A. area will largely flood into cafes and co-work-esque places as businesses start opening back up and remote work becomes more dominant.