I would guess that fall/winter is a good time to be in the portrait business. There are so many family gatherings and reasons to have portraits done (with the exception of HS portraits, which I guess are done in the spring, and peak US wedding months are probably May-August). So many people thinking, hmm, what will I give grandmom... yep, a portrait.... plus there just seem to be many more reasons to dress up in the winter months.
I would also think that from a business standpoint this is a great time to lock in any loans and such. We are about to see much less favourable interest rates. Ironically, the best financial policy right now seems to be to go into debt as far as they will allow you.... and pay later!