Many cultures celebrate the event in some manner, and the 1st day of January is often marked as a national holiday.
In the Gregorian calendar, the most widely used calendar system today, New Year occurs on January 1 (New Year’s Day). This was also the first day of the year in the original Julian calendar and of the Roman calendar (after 153 BC)..
During the Middle Ages in western Europe, while the Julian calendar was still in use, authorities moved New Year’s Day, depending upon locale, to one of several other days, including March 1, March 25, Easter, September 1, and December 25. Beginning in 1582, the adoptions of the Gregorian calendar has meant that many national or local dates in the Western World and beyond have changed to using one fixed date for New Year’s Day, January 1.
Other cultures observe their traditional or religious New Years Day according to their own customs, sometimes in addition to a (Gregorian) civil calendar. Chinese New Year, the Islamic New Year, the traditional Japanese New Year and the Jewish New Year are the more well-known examples. India and other countries continue to celebrate New Year on different dates.