While late spring and early autumn are my favorite times for cycling, each season has its pluses and minuses. In winter the pluses are no bugs, no thunderstorms, fewer pedestrians on MUPs, more space in the bike racks, and the serenity of riding along quiet, dark roads. Plus, there are rarely moments during the year more beautiful than riding in a light snowfall on a lighted street.
That said, winter happens no matter what, and you can choose to ride through it, or take a few months off. I love cycling so much that I'd rather ride, no matter the weather.