January 1 is far from the only New Year's Day. Many cultures have other New Years spread throughout the seasons:
Click the chart for a version better designed for smartphones. (Please note: this chart shows a small subset of the many New Years that exist among the many cultures on Earth. Because of cultural complexity, it was necessary to combine both religions and nationalities on one chart. Obviously, some people in these countries may have different religious or cultural traditions. Multiple-day holidays are marked on their first day. Holidays that start in the evening are marked on the day of the Gregorian calendar on which that evening falls.)
In 2015, many of these holidays will appear on different dates. In most cases, it’s because they are based on lunar calendars (like the Chinese, Jewish, and Islamic New Years are).
The Persian New Year celebrated in Iran is determined by the Northern Hemisphere’s vernal equinox and can also shift around from year to year.
Our own American New Year is fixed to the Gregorian calendar, which Pope Gregory XIII established in 1582 to account for a discrepancy of 10 days that had accumulated since Julius Caesar had borrowed the Egyptians’ 12-months-and-365-days-plus-leap-years format. (Earth’s trip around the Sun is — inconveniently — not quite 365.25 days long.) Gregory XIII also moved the New Year from March 25 (the Feast of Annunciation) to January 1, where it still stands today.
