Working a tree mid winter without protecting the tree afterward may result in cold damage. I wire most of my pines from December through March, but I've got a cold room where the temperature rarely falls below freezing and there are obviously no drying winds unless the windows are opened (they aren't right now). The more twists and bends a branch experiences with wiring, the more microdamage the cambium suffers. Bringing a tree inside and working on it for a day then back outside is fine, but protection from hard freezes and wind is important after the work is done.