David Z, hello.
Over the years, Seattle Parks has had a number of requests about nudity in parks: some requesting that we designate one or more “clothing-optional” beaches, and some requesting that we create a rule against nudity. Seattle Parks has declined to either support or prohibit nudity.
When people ask, we explain that nudity per se is not illegal in the state of Washington, and quote RCW 9A.88.070 that for behavior to be considered “indecent exposure,” there must be a determination that a person has caused “affront or alarm” to another person.
Superintendent’s Office, Seattle Parks and Recreation