Here is a nice graph from Calculated Risk that you can click on to get full screen. I would like to find month by month data in numerical form.I think you see a lot of spikes in this graph in the early spring but it is by no means completely consistent.Certainly has a lot of “V” shapes on the trend line, both large,usually pegged to recessions,and small. The idea that this is seasonal blip, against otherwise bad times, probably has a lot of merit though.