Shoot Like it is Winter in June
Practice like you hunt is often a tip given to bow hunters. They are reminded to practice in their hunting clothes so they can detect any problems with interference in drawing the bow before they are in an actual shooting situation.
It is good advice for bow hunters and for rifle hunters. A lot of my shooting practice happens in the spring and summer where I shoot in a t-shirt. This is great for comfort and staying cool, but it does not simulate how you will be dressed in the winter. I have hunted on days so cold that I put on a heavy jacket, down vest and multiple layers of clothes.
The affect of wearing all of these clothes was not just that I stayed warm, but it changed the length of pull of the rifle. This not only affected where my eye lined up for the scope, but how my finger sat on the trigger.
Fortunately, I had plenty of time to readjust and make the shot, but had I needed to make a quick shot I would have been out of luck. It took just a minute to figure out what was wrong, but I am sure during that time I would have lost the opportunity to make the shot if the buck was anxious and moving.
It might get you some strange looks, but pack your heavy hunting gear including gloves to the range with you before hunting season and take a few shots with all your winter gear on. It will make sure you do not have any surprises on that cold day when the buck of a lifetime is in front of you.