From what I have learned, horses handle the cold good, and the wet, but the cold wet gets too them. I rarely blanket until March, and that's only to help rub the winter coat off.
My horses have free choice to go in or out. It use to drive me nuts that they would stand out in the snow or cold wind when they could go in if they choose. Now I just don't worry about it. They've made their choice, they can deal with it:)
Becky
When I was growing up my horse had free choice to stay in or go out. She did stand in the rain sometimes. duhhhhh We had a horrible storm once, with golfball size hail, and she wouldn't go in the barn. It was a tin barn and the hail sounded like gunshots. She was running and screaming and the neighbors horses were running and screaming. My mother and I were at the window watching, screaming and crying. Still upsets me when I think about it. I ALWAYS bring my horses in when I know there is a storm approaching.
No lasting injuries on the horses, amazingly enough.