I don’t see any problem with the connection in CLT in Jan. It’s extremely rare to get snow in CLT. The late departure is an issue out of BOS but typically they don’t like to cancel the last flight of the night. One thing you have going forward is if a major weather event is forecast in BOS they typically a few days prior offer free flight changes. There is also a later flight out of STT from CLT. That could be a option if you had to take the first flight out of BOS in the morning.