I moved to CA in ‘73 from the east and midwest living in the Bay Area. Most of my sweaters were bought in Monterey or Carmel. We’d leave a nice 75 or 80 degree summer day in the Bay Area and get to 55 or 60 degrees on the Monterey Peninsula. It never failed — I always forgot to bring a sweater or jacket with me.
I had to buy a sweatshirt during a July trip to San Francisco.