Depends on the country. Mine doesn't have laws about that, other than "disturbing the peace". You can disturb the peace during the day too by revving an obnoxious motorcycle for instance. But no hours are codified as "night time" or "day time". Only place it appears is blocks of flats, where the community can set it, when it's binding. Also they can set it to be during any time they want it, so if a night owl sets it it could get weird :d