Before the last year the best time was when the "Spring" season started which was after the Super Bowl season ended. Some people laugh when hearing that but it was true. Showings and open house increase after the football season was over.
The other thing different is that this year there has been horrible weather and a lot of snow so there may not be as big a upswing in the amount of listings put on the Real Estate Market starting Monday morning since the Professional Football season will be over.
So to answer your question, put it on the market when you are ready to sell.