Our season changes too rapidly for maximum colour. I remember the vibrant reds and neon oranges when I was a kid.....but the last decade has gone from green to yellow to brown to raking.
*I just re-read that, and it sounds like I think I was a kid a decade ago.
The colours come from the sugar content in the leaves...and needs the right conditions to change the chemical change slowly. The brightest autumn colors happen when dry, sunny days are followed by cool, dry nights. Our blasted 'moisture' is messing things up.