In the southern Rockies, the leaves are either gone (up around 10,000 ft MSL) or going (around 9,000 ft) or still have weeks to go (below 7,000). That's one of the many things I love about the southern Rockies ... fall lasts just about as along as you want, depending on where you're sitting, elevation-wise. The cottonwoods in the river bottoms are good through about mid-November, while the quakies on the high mountain ridges start turning in early-mid September.
Fall is also the best flying weather - the winds are much tamer than winter or spring, the T-storms are much fewer and farther between, and the valley fog is pretty much gone. Love the fall!
