I heard an amusing story last night. It seems about 20 years ago my family was bicycling along marine drive. Then to naked people walked across the road to the beach. My Mom, being some what conservative, called the Portland Police. They said it wasn't their territoy, call the county. The Count said it wasn't theirs either. In the end, after calling city, county, state, and port authorities she reached someone in city hall who knew the law. It seem at the time (I have no idea what the law is now) you could go fully nude in Portland as long as you were not doing anything lewd (touching yourself, etc).
I think I know how to beat the heat on these 90-100 degree days. :-)