Tip:
Winter can be an easier and more difficult time to carry a firearm. Often, we find that we can get away with carrying a larger firearm due to heavier clothing. Some problems can also arise with the winter carry.
Access:
Gaining access to your firearm through multiple layers of clothing can be a challenge. Often the extra layers can have a constricting effect, making it more difficult to remove your firearm from the holster. You may need to consider how to layer your clothing in a way that keeps it from fouling your draw.
Snags:
Another thing that comes with many jackets is an elastic cord to keep the jacket sealed at the bottom. These, in use or not, are a significant hazard for snag on the draw. Unless you actually use this cord, it is prudent to remove it from your jacket.
Transitions:
When considering what type of concealment you choose, always consider your destination as well as the trip. It can be easy to think that your concealing garment is sufficient until you have to doff a heavy jacket because it is too warm indoors. Consider what your concealment would be without your outer layer.
Fingers:
When outdoors in the winter, gloves can be a hinderance to the concealed carrier. When making a choice in what gloves (or firearms) to purchase, consider how they would work in a concealed carry context. Does your finger fit in the trigger guard? Can you operate the controls effectively? Can you still grasp your spare magazine and reload? Is there excess material that might catch in the chamber during malfunction clearances?
Remember that differences in wardrobe can cause more problems than you may consider. Pay attention to what your needs are when the cold weather arrives.