In CA and other states, the local laws are what drive variability. There is also enforcement – in both San Francisco and Palm Springs, bit are known to be forgiving even though there are laws against public nudity. There is a neighbor in SF where nudity is illegal; however, they enforce a “skid mark” where you are ok as long as you have a towel to sit on. In Palm Springs, they will merely tell you to get dressed and maybe a $100 fine (provided that you are not being lewd).