Delving into Dwemer ruins and reading ancient tomes that expand the complexity and depth of lore, and thus, each person's subjective perception of Mundus has more hendonistic value when it is cold and snowing outside, as the role-playing experience of a survivor in a frozen world is more appropriate during this time of year. It is more socially acceptable to engage in dissociative activities during winter.
I live in one of the best Winter cities in America, and there's arguably more to do in the winter than there is in the summer. That being said, those prone to dissociation will usually double down during winter, as there are more reasons (excuses) to do so. Those prone to achievement will find ways to continue achieving irregardless of the conditions of the external world.