The Smokies in September-Weather Questions?

[sadlowskiadam]

I will be hiking The Smokies for about a week starting September 14th. I hiked The Smokies during my 2013 thru hike, but that was in the month of May (cold rain the whole time). I was wondering if anyone could give a sense of what kind of weather to expect in The Smokies in the middle of September? Would a 3 season sleeping bag still work or should I go with my winter sleeping bag? Thanks for the help in advance.

[MuddyWaters]

Warm days, cool nights in 40s at highest elevations.
Low elevations are hot days and hot nights

For instance, clingmans dome average high is 60, average low is 47 in September.

40 F bag is perfect imo

[HooKooDooKu]

I do a hike to LeConte Lodge every year about mid-September. Not surprisingly the weather changes year to year. There have been years where temperatures have been below freezing, and years where night time lows are in the 50s. So your best bet is to check the forecast just before you leave to know for sure.
Typically, these last several years has had warmer weather that we often experienced 15 years ago. September is also a month that receives the least rain fall.
Check with Mountain Forecast before you go.