Opt for thick, warm fabrics that will keep you cozy without making you feel suffocated. Some good options include wool, cashmere, tweed, or herringbone. Stay away from linen, seersucker, chambray, and cotton, all of which will be too lightweight. There are no hard and fast rules, but in general, darker colors tend to work better for winter weddings. Classic shades like black, dark navy, brown, or charcoal always work, and if you want to do something more stylish and interesting, you can go for oxblood, burgundy, hunter green, or plum.