I believe this question is best answered by evaluating when buyers make an actual buying decision -- which is when they sign a contract.  The data above shows when buyers sign contracts -- calculated by averaging data from the three most recent years.

As can be seen, the busiest buying season is March through August when an average of 130 buyers per month make a buying decision. 

The remaining six months of the year (September through February) show anywhere between 51% and 74% as many buyers as the average of 130 per month seen in the busiest six months of the year.

So -- listing your home on November 1st (for example) is not a terrible idea -- we'll see 62% as many buyers signing contracts in November as compared to the average busy month.  That said, in the following month (December) we're likely to only see half as many buyers as compared to the average month.