Forgive me if this is a double-post, but it appears my first attempt didn’t go through as the website locked up on me. Anyway, the OP was: How did San Francisco become the hippie central, USA? What was the big draw to San Fran…enough to even write a song about it?
Be sure to wear flowers in your hair,
WAG: proximity to Berkley and Timothy Leary? He was, after all, the King of the movement.
Ok, so what’s the SD on Timothy Leary? As I understand it, he found one in a million kind of mushroom that gives one a high when ingested, correct? Were these “shrooms” unique to the SF area? Or, just easily obtainable in SF, I WAG?
Is that what all the hub-bub was about?
Berkley is close to Los Angeles, not San Francisco. That’s a fair bit farther north – like an 8-hour trip.
No, Leary was big on LSD, which had been known for quite a while. Leary thought that it was a true “mind opener”, giving the user unusual powers of perception (as opposed to just making them psychotic).
Better look at a map.
No Berkeley is across the bay from San Francisco.
It seems to have started earlier, with the pre-Beat Modernist poets and the Beats after them. A few gathered, drew in more, and there was enough critical mass of this artsy counterculture, along with fresh fuel from Stanford (where LSD trials were going on), Berkeley, et al.
Leary was at Harvard during the late 50s, early 60s and lived in the East even after he got kicked out of Harvard. He was present at the Human Be-In during the Summer of Love, but SF was already Hippie central by then.
The Hippie culture in SF probably arose out of the Beat culture there with folks like Allen Ginsburg, Neal Cassidy and Alan Watts.
Yeah, I always thought it had to do with the City Lights Bookstore. It published a bunch of Beat stuff, including Ginsberg’s “Howl” and was a gathering spot for the bunch of them.
So if you wanted to get away from the squares, that’s where you went.
That’s exactly what I had in mind-- I had originally put it in my post, but thought it might be too obscure a reference. SF had a reputation as a wild place going way back, so the Beat movement might have been just the 40s/50s version of that.
There was a special on cable recently about just this subject. The conclusion was that the presence of the Beats was the major factor.
I’ve lived in both LA and San Francisco. Berkley is maybe 20 minutes from SF. LA is less than 6 hours South of both.
I’m sorry, that you must live in that alternate universe. We’ll see if we can smuggle you back soon. 
How did Battle Creek, Michigan become “Cereal City”? How could Lennon and McCarthy both come from Liverpool at the same time? Why are there an abnormal amount of great jazz musicians from Pittsburgh? Why do obese motorcyclists congregate in Sturgis, SD?
Sometimes a confluence of events happen to foster a condition where similar things that exceed the norm concentrate in a particular geographic area.
I suppose that statistically it’s bound to happen. It’s just hard to predict where it’s going to happen.
The Aztecs used to use mushrooms, and many species of psilocybin containing mushrooms have “aztec” as part of their scientific name.
I don’t see why the trip to San Fran to Berkley couldn’t be an eight hour long “trip”. 
It could be over Labor Day weekend, when the Bay Bridge is closed.
Not to pick on you exclusively, but:
Berkeley is also spelled like that.
Ed
By gad, you’re right! And here I couldn’t think of anybody past Earl Hines.
My guess is it was the bad air. The best jazz always comes from someplace kinda icky.
You’re right.
It could be that both counter cultures grew there, because, the area is, historicly, more accepting of diversity.
I think it’s because of the Goldrush, The Chinee, and its situation as a major Pacific schooner port.