In general, is January a slow month for most people compared to other months? Maybe it's just me, but I've noticed that trend over the past 3-4 years since I started.
Yes, generally middle of December to middle of January is the slowest period of the year for me.
For people with lots of Christmas stuff (and fireworks) it might be one of the best periods. In December, sales shift very heavily toward anything related to Christmas, New Years, and winter (for music, footage and images).
My strongest periods are usually April-May + October-November.