> In a world context, beginning the year in spring is normal; beginning it in the middle of winter is very weird indeed.
The character of the seasons is rather local. For example take the Greek legend of Persephone and Demeter and the Sumerian legend of Dumuzid and Inanna. Both explain the seasons by a god being trapped in the underworld for half the year, but the Greeks considered winter the dead time while for the Sumerians it was summer.