Charles Dickens's novella A Christmas Carol opens on a “cold, bleak, biting” Christmas Eve. The day has been dark and cloudy, and candles burn in the windows to try to dispel the gloom. The weather reflects the nature of the story's main character, Ebenezer Scrooge, who is “hard and sharp as flint.” The narrator relates that
The cold within him froze his old features, nipped his pointed nose, shrivelled his cheek, stiffened his gait; made his eyes red, his thin lips blue; and spoke out shrewdly in his grating voice.
Scrooge is cold as ice. He cares for no one, freezes everyone out, and does not even thaw at Christmastime.
This emphasis on cold (both physical in the weather and emotional in Scrooge) provides an excellent setup for a story that is all about thawing out that ice and warming things up with Christmas cheer and good will and love. If Scrooge was not cold and biting, the change that comes over him later would not have nearly the same effect. But, of course, he is, and we see him thawing gradually as the story progresses.
The Ghost of Christmas Past reminds him of a time when his own heart was warm and loving, when he overcame the chill of his childhood and found love. But it also shows his gradual cooling as the ice inside him grew along with his love of money.
The Ghost of Christmas Present reveals the warmth all around Scrooge that he never even notices. He now sees the warm love of the Cratchit family and is touched by the love of Tiny Tim. Scrooge's heart begins to thaw just a bit as he realizes that people don't have to match the frigid weather around them. They can choose to be happy no matter what their circumstances.
The Ghost of Christmas Future chills Scrooge's heart in a new way, with fear. Scrooge realizes for the first time that “cold, cold rigid, dreadful Death” will one day overcome him, and there is no escape. He also witnesses the grief of the Cratchit family at the loss of their beloved Tiny Tim, and the ice in Scrooge's heart breaks for good. He rises on a bright, sunny Christmas morning a new man, filled with warmth and love and joy.