That is actually not what I have observed. I researched prices for 3 years before buying mine and found that prices actually dip in the spring/early summer, especially on convertibles. I think the reason is that prices have bottomed out throughout the winter and everyone has been saving their Vipers for a better market. The problem is that this floods the market and eventually people that need to sell panic and it drives prices down further. I have found that August/September is the worst time to buy.
Where I am, prices are at thier absolute lowest at this time of year. Conv., Coupe, w.h.y. I did my due dilligence, as well. Perhaps a local phenomenon, perhaps and economy factor (boom here for the last decade) but certainly before I bought, (and before my brother bought) and since, the prices have been the lowest in the dead of winter. THis is not unique to Vipers, either. When spring hits, the prices rise, no deviation in the past 6 yrs.that I've been watching, all gens. Highest in July/Aug, sharply dropping by Dec.
Sept. may be the worst time to buy for several reasons, not the least of which would be the lack of dry driving time left, if you're in a "wet/cold" area. But buying in the dead of winter has few advantages other than that the prices are low. Three in my area have bought in the last few weeks, it's killing them to sit and wait it out, but they got good deals.