Although I should only be considered a beginner in this market, I've found the market to be tightening in the past few months. Specifically in the high end of diamond buying. I heard a rumor, could be way off on this, but the international wholesalers aren't buying as much do to the cost of inventorying large stocks that can't be sold in a contracting market since Sept. Diamonds are, in fact, a luxury item.
As for the seasonality, I would think that it's always a matter of demand and supply. If there is more demand, prices will go up, unless there is a corresponding expansion in supply. If the above rumor is true, you may be facing higher prices, however, I doubt that this will generally apply to the whole market. If you have something specific in mind, I would suggest that you start your research a bit earlier than you had intended; and to be patient.
Good luck!
