Some thoughts on nine nights in Argentina in winter - Four nights in Buenos Aires is not too much. Colonia is very pleasant and it can indeed be visited in a day. bit there are many more interesting destinations . . but FAR more interesting would be a trip to Salta and the altiplano via Movitrek or similar excursion outfit, or Salta and the Quebrada de Humahuaca, or Salta-Quebrada de las Conchas-Cafayate - and perhaps down to the ruins of Quilmes, just 54 km further. While it can be beautiful, Bariloche in August is way too cold unless you plan to go skiing. I just returned from three weeks in the country, where a colder than usual winter is projected. Buenos Aires winters are humid, increasing the sensation of cold. Nights in the Northwest (NOA as known locally) are cold, but days are very pleasant indeed and rain is very unlikely. Igauzu in this season is also a good choice. You don't need more than two nights there unless you are a fanatic bird/butterfly watcher.