"Hang around " is more of being in a place without doing something useful ,just passing time with no aim ,so when you say that someone is hanging around a place ,it doesn't give a positive impression about him , while the " hang out " is the regular place where one would meet his/her friends ( like a club , pub,) usually for food and chat ,like you can't be hanging out in the cinema for the time of your stay there is limited by the movie's length ,while the hang out is not limited in time ,so it is a flexible and laid back outing .

Hang out generally means something like spending time with friends in a very relaxed setting. "We're hanging out at Josh's house." Hanging around is very similar but may hold a slightly negative connotation (This depends highly on how it is used though). Like someone could say "Yeah, he's been hanging around here a lot lately." depending on how it's said it could be inferred that the speaker does not like the person around so much.

Hang around:to stay in or near a place not doing very much.(for instance:i really hate hanging around in airports) Hang out:to put washing ..etc on a clothes-line so it can dry

en español pienso que sea "pasar el tiempo (con amigos)"