In 'a winter's day short story', themes like change are likely. Winter brings a significant change in the environment, and the characters might also experience personal changes during this time. Another theme could be beauty in simplicity. The white snow, bare trees, and quiet winter days can represent a simple kind of beauty. And finally, the theme of introspection. With the long, cold winter days, characters may have more time to think about themselves, their lives, and their relationships.
One possible theme could be isolation. Winter often makes people feel alone, and in a short story, the main character might be physically or emotionally isolated. Another theme could be survival, dealing with the cold, finding shelter, and getting enough resources to make it through the winter. Also, renewal might be a theme. Just as winter is followed by spring, there could be a sense of hope and new beginnings at the end of the story.