We have an upcoming hike in the Linville Gorge (NC). Reports say that a bridge is washed away, and you have to be prepared to wade or even SWIM across. If I'm going to swim, I'll take late summer.

Most of the time spring and fall are the best times. But if the weather is moderate, even mid-winter is a good time to hike, though short days are a problem. Interestingly, it wasn't all that long ago that I came to the realization that the fall season and winter season have exactly the same amount of daylight. Likewise the spring and summer seasons have the same amount of daylight. What's different is the amount of heat.