I usually visit my daughter in San Francisco when the temps hit 100+ for days on end in Southern California - often September.
Nothing like hitting 65 degree fog after driving up the Golden State freeway in 110+ temps - the dogs refuse to get out of the car at the rest stops.
A couple years ago went to the races at Golden Gate Fields. Just closed, but right in the bay at Berkeley. We were having a heat wave at home. There was a 42 degree swing from when I got in the car to when I got out at home