The park usually experiences an autumn leaf season of several weeks as fall colors travel down the mountainsides from high elevation to low. However, the timing of fall color change depends upon so many variables that the exact dates of "peak" season are impossible to predict in advance.
Elevation profoundly affects when fall colors change in the park. At higher elevations, where the climate is similar to New England's, color displays start as early as mid-September with the turning of yellow birch, American beech, mountain maple, hobblebush, and pin cherry.
From early to mid-October, fall colors develop above 4,000 feet.
The fall color display usually reaches peak at mid and lower elevations between mid-October and early November. This is the park's most spectacular display as it includes such colorful trees as sugar maple, scarlet oak, sweetgum, red maple, and the hickories.
Autumn is both a beautiful and busy time in the Great Smoky Mountains. The annual show of fall colors attracts huge numbers of sightseers, especially during the last three weeks of October. Areas in the park which experience the longest traffic delays are Cades Cove and Newfound Gap Road (U.S. 441).
Why are fall colors so remarkable in the Smokies? One reason is the park's amazing diversity of trees. Some 100 species of native trees live in the Smokies and the vast majority of these are deciduous.
How do colors change? As summer ends, the green pigments in leaves deteriorate, giving other colors a chance to shine. Carotenoids, the pigment that makes carrots orange and leaves yellow, are exposed as the green fades. Reds and purples come from anthocyanin, a pigment that is formed when sugars in leaves break down in bright autumn sunlight.