The summer coloration of the trees in whatever place I select at the present time seems to be more Autumnal, with vivid oranges, reds and other shades. My date is correct and the selected season is "Summer".
I know that the Autumnal colours in New England are a magnificent sight and the same is true in wooded parts of the UK, particularly Surrey in the vicinity of Leith Hill. However early-mid September seems a bit too soon to be seeing such brilliance in either location - correct me if I am wrong!
I altered my seasonal setting to Spring and the green appeared.
For $60 I don't think you're going to get a computer model for every leaf on the planet. Set your date to whatever floats your boat - that's why it's there.