Fall Colors, Minnesota North Shore, Lake Superior, Duluth, Grand Marais, Tofte, Lutsen, Two Harbors, Grand Portage, Cook County, Lake Country, St. Check out our 20 fall color tours Autumn on Minnesota's North Shore of Lake Superior will leave you with incredible impressions. The fall colors peak between the first week in September and mid-October. The rewards are spectacular.
Leaves change color due to shifting rhythm of the day and night.
The long warm days of summer eventually turn shorter and cooler, which triggers a chemical clock inside the deciduous tree to enter winter sleep or dormancy. But as fall approaches the tree enters dormancy and stops producing food and chlorophyll. So as the amount of chlorophyll diminishes, a group of pigments called carotenoids start to show. Carotenoids are the yellow, brown and oranges colors we see during fall. Deciduous trees on the North Shore are sugar maple, red maple, silver maple, aspen, ash, birch, and black cherry.