The color of banana peels typically ranges from green to yellow, depending on the ripeness of the banana. When bananas are unripe, their peels are green, gradually transitioning to a vibrant yellow as they ripen. As bananas continue to ripen further, the peels may develop brown spots or become entirely brown, indicating overripeness. It's important to note that there are variations in banana peel colors among different banana cultivars, but green and yellow are the most common colors associated with banana peels.