It just seems like it's difficult for the urban areas from NYC southward (maybe even BOS these days) to get that cold absent a real fresh shot of arctic air (that is usually fleeting). It wasn't exactly balmy today (NYC high of 44, DCA 50), but NYC is around 36 now at 1am, and DCA is at 41. Here in Tenleytown we've basically been stuck around 38-39 for the past several hours. Most nights, we stay above freezing.