Chamblee54

One thing that is accepted without question is the year starting at midnight on December 31. That is, in some cultures. Jews have a new year in September, China celebrates some time in January, and the fiscal year is whenever the bean counters say. If you ask google “why does the year start january first”, you get 436m options.
The earth runs on a cycle, based on it’s annual trip around the sun. The winter solstice is the longest night of the year, and in many ways the logical end of the year. The celebration of Christmas, a few days after the solstice, is not a coincidence. The question today is, why do we start a new year a week after Christmas, or ten days after the solstice?
The top ranked answer at google is from catalogs.com. They talk about Julius Caesar and Pope Gregory XIII(13), but never quite say why January first is the big day. It does end on a helpful note: “Calendars are a way that grownups organize time, but clearly not all grownups do it the same way. Happy New Year, therefore, whenever it happens for you.”
Lifeslittlemysteries continues with the talk about Caesar and the Pope. It is noted that January 1 was the day that Roman officials started their term of office. In England and her colonies, the new year was celebrated in March until 1752.
The rest of the google results do not look promising. PG does not know the answer to this. Maybe the best answer is that the New Year starts January 1st is because the calender says so. This is a repost. Pictures from “The Special Collections and Archives, Georgia State University Library”.