While in America and England Christmas Cards tend to be the norm, in France the custom is to send New Year’s cards.
Cartes de Voeux, literally translated as Wishing Cards, are usually sent out in January, and convention has it that one can wish your friends Happy New Year right up until January 31st.
What a charming idea!
Instead of adding Address-Envelopes-for-Christmas-Cards to your already endless do-before-Christmas list, one has the leisure of four weeks to get around to sending good cheer. 
Right at the moment when the weather is grim, and everyone is financially, or possibly physically, hung over somehow the notion of an entire month devoted to wishing people a healthy and happy new year makes the month of January entirely more palatable. 

Further more, Wishing cards are much more open to interpretation, certainly not limited to Merry Christmas, and Happy New Year. One can wish health and happiness of course, but one can wish lots of others things as well: beautiful vacations, or tender love affairs, memorable moments, creative thoughts, the realization of dreams, adventures, success, new discoveries, accomplishments or serenity to take just a few ideas from some that I have received in Paris recently. Wishing you a luminous new year is a particularly poetic and Parisian thought.

So, take a cold, rainy January moment to think happy thoughts about the coming year, and if you are so inclined, allow yourself to be inspired by the French and spread some joy in a month that could really use some!