These include items such as blackberries, blueberries, whortleberries, mulberries, pokeweed, citrus, plantains and bananas. Weighing an average of 30 g and reaching lengths of 17 cm, the Summer Tanager is rather large in comparison to other tanagers. Their light brown bills are pointed, and fairly stout. The adult male has red plumage, ranging from bright rose or orange-red throughout the year, and is brightest on its underparts. Unlike the male Scarlet Tanager, the Summer Tanager has paler plumage, not intense scarlet, and reddish wings and tail rather than black.
Some females gain complete male pigmentation as they advance in age.
The plumages of immature birds are similar to the female's coloring. One study found that Summer Tanagers in a lowland of Ecuador all had dull, female-type plumage. Additional observations found that most sightings of at higher elevations in the Andes are of adult, male-plumaged birds. This may suggest elevational preferences by sex during wintering periods in South America. Interestingly though, in Central America, both sexes are found wintering together.