According to the Winter Winds Songfacts, the "Winter" in this song is a metaphor for loneliness as the narrator finds himself with a girl as he's lonely. He wants to love her, but is unsure if he is with the girl because he has feelings for her, or because of a fear of being alone.
As the winter winds litter London with lonely hearts
Oh the warmth in your eyes swept me into your arms
Was it love or fear of the cold that led us through the night?
For every kiss your beauty trumped my doubt