The air is cooler, the visibility from the summits are usually better than in the summer, and the leaves on the trees can make the trail glow as if it was on fire.

LIVING THE LIFE, ONE HIKE AT A TIME
The air is cooler, the visibility from the summits are usually better than in the summer, and the leaves on the trees can make the trail glow as if it was on fire.
There have been a lot of incidents recently where hikers have gone missing on trails that are known to be very warm in the summertime. With the proper preparations you can prevent these kinds of problems from happening to you.
In hiking, the amount of elevation gain, or to quote Wikipedia, cumulative elevation gain, or simply gain, is what makes a trail steep, really steep or not so steep.