Although your acer started off dark red as the season progresses the red will fade more and more and the leaves will start to look a reddish/green shade. This is perfectly normal and will happen every year. Next spring the leaves will start off dark red again.

Getting ready for autumn - this happens earlier if the weather's been dry and you don't intervene and water.

Thanks for the info. I have never noticed this colour change before this year. Yes a dry year, though I have watered with relative frequency.

Certainly wasn't a dry year here!

Depends where you live Steragram, we have rain today for the first time in a fortnight and we need it, the grass is brown everywhere with all the hot sun we've had.