In the United States and Canada, leaf peeping is the informal term for the activity of viewing and photographing the fall foliage in areas where the leaves change color in autumn, particularly in northern New England, Appalachia, and the upper Midwest, as well as Ontario and Quebec.

Colors typically peak in Colorado’s northern mountains during the month of September. The central mountains reach their highest point in the last week of the month. It’s the first week of October in our southern mountains.