When I retired from the Navy on 12/31/93, i drove up to Oakland CA from San Diego CA.
I shared a really nice apartment with an old friend for a couple of years. I do not recall ever getting so warm in summer that I wished we had A/C. At that time, Oakland was always cool enough in evenings for a jacket or sweater no matter what time of year it was. A "hot" day was in the low 80s, and it never seemed to be the norm.
When I moved into my own condo in 1995, the weather was much the same in the Bay Area. I had a window fan in my bedroom, and that was all I ever needed.
However, as the years moved on, we had more and more really warm days. It got to a point where I had to go to Sears and buy an a/c window unit. Bay Area houses and apartments simply did not have air conditioning. They had fireplaces, though, which would often be lit in the evenings on cool summer nights.
By the time I retired a second time, there were no oool summer nights. I had a/c units in living and bed rooms. And I used them daily during the summer.
Here in SC, there is no point in NOT having a/c. I set my thermostat in winter and summer and the HVAC system maintains consistent temperatures for me in the house. There is only a brief period in spring and fall when the system does not come on at all.