In most of the world, it is taken for granted that one day ends and the next begins at midnight. But this is purely arbitrary. For example, from about the second century until 1925, astronomer counted days from noon to noon.
For most primitive tribes, the new day began with sunrise. This system continued with the Babylonians and Greeks. On the other hand, for the Jewish people, one day ended and the next day began at sunset. In other words, the late evening wasn't the eve of the next day - it was the next day. (By that reckoning, a New Year's Eve party would have to begin at about 4 p.m., and the whistles and cheers would erupt at 6 p.m.)
- Little Black Book, Diocese of Saginaw