Despite the robust climate, Germans are generally a lot less reluctant to take off all or part of their clothing in public than most peoples. Still, community standards in different parts of the country vary considerably. The full nudity tolerated in Munich’s Englischer Garten, for instance, would never do in Dusseldorf’s Hofgarten, say.
Topless sunbathing at various outdoor swimming pool complexes has long since been the norm; topless swimming is somewhat more problematic. Sometimes at the lakeside or on beaches, generous parts of outdoor recreation areas are screened off for nude sunbathers and even wild geese.
Incidentally, the German euphemism for nudism is FKK, which stands for Freikörperkultur (free body culture). The sauna facilities at various indoor pools, where people tend to frown upon foreigners in bathing costumes, are often mixed. Most do though offer a Damentag (ladies’ day) on odd days of the week; there is normally no Herrentag (mens’ day).
Watch out for this popular pastime in some hotel saunas too! A fascinating society.