…is always expect the worst. In the Smokies, March weather can be real nice, but it can also be brutal. Moreover, sometimes it can change from one to the other within a few hours.
If your memory is short, do a web search on the “March 1993 Superstorm”. That storm hit in mid-March after a couple of beautiful sunny days. It left several feet of snow up and down the spine of the Appalachians with the Smokies getting the worst of it (Mt. Mitchell in NC got 50" and Mt. LeCont in TN got 54"!). In addition to several FEET of snow, the storm was followed by several days of extreme cold. The end result was that, even though the storm was well forecast, there were literally hundreds of hikers stranded in and around the Smokies who had to hunker down for at least a day or two (and sometimes a lot more) in very cold and windy weather. I suspect that any who were caught in that storm with a 20-degree bag were, at best, extremely uncomfortable… at worst, they risked their lives.
Obviously, that is an extreme case, but, if you really want to be safe, you should assume it could happen again.
Ken G.