Four or five months: from november to march. But in Wrocław Zoo they have access to outdoor for hour or two even in winter months. I suppose that is just the same in Poznań Zoo.
The elephants in Warsaw Zoo are allowed out whenever the temperatures are only a few degrees about freezing and are only confined indoors in the lower single digits and into the negatives (degrees C of course), I would assume it is similar in many zoos in colder climates with elephants.
