The winter suit is heavier and thicker than its summer model, and for good reason. Summer suits can be down right cold when its snowing and the wind is chilling you to the bone.
Cold weather models will be made from traditional wools or wool/polyester mixes. Consequentially, they will be thicker than their brethren. They may also have a bulkier inner lining for maximum heat retention.
The tweed suit, heavy wool suit, and the flannel suit are the three main models you can expect to find on the winter weather suit racks. These materials have been keeping people warm for years and work just as good today as they did for our fore fathers.
A side benefit to the heavy wool used to make these suit is a noticeable reduction in wrinkles during day to day use. The thickness of the suit makes it hard for the suit to crease or fold up in any meaningful way, so you generally get less wrinkles.
This being said, if you are in love with your summer suit, I’d advise keeping it and throwing on an overcoat when needed. Of course, this only applies to summer suits made from wool or wool/polyester materials.
Cotton, linen, and seersucker suits are never appropriate for winter weather wear.
If you’re in the market for a nice winter suit, you’ll find that all designers have something suitable to wear during the cold weather months and you won’t have any trouble finding something you like.