Sheesh, you all forgot that Salem is under a dome of some kind. Thus it has no snow at all, leaves on trees in January, and of course the magic elves that put the Christmas decorations up, and then take them down without a soul seeing them. Oh, it has a couple places where fresh air comes in, thus they get some colder air, but they don't have to button their coats, wear hats, put their scarves around their necks INSIDE their coats or jackets, and heck, can even wear their summer clothing.
I guess the set people, wardrobe & directors really have a problem thinking of cold, and snow when trying to film thanksgiving in August and Christmas in September. Probably hard to get "in the mood". LOL