It depends. Right now, I have some of my older girls and ducks have started molting. But, last year I had girls that didn't start molting until Thanksiving or later. I think the dmapness - and the fact that some many of mine went broody (hence, post broody molt) is why I've got a fair number in early stages of molting now.
I suspect that you will start to see early signs of molting sometime between now and Columbus day, with the heavier part of the molt after that.
Again, though, it varies.

They always keep me guessing - and I've had chooks fo a number of Falls now.