New year is the start time or date of a new calendar year. The calendar year count is increased by one.

Many cultures celebrate the event in some way, so January 1 is usually a national holiday.

In today's most widely used calendar system, the new year occurs on January 1 (New Year's day). The same is true in the Roman calendar (at least around 713 BC) and the subsequent Julian calendar.

Historically, other calendars have been used in other parts of the world. Some calendars count years in numbers, while others do not.

In the middle ages of Western Europe, the Julian calendar was still in use and, depending on the region, the authorities moved New Year's day to one of several other days, including March 1st, March 25th, Easter, September 1st and December 25th. Since 1582, the Gregorian calendar has been adopted, and the "old style" and "new style" dates have been changed, which means that the various local dates of new year's day have been changed to use a fixed date of January 1.

The Gregorian calendar, which is officially widely adopted and has January 1 as the start of the new year, is now almost global. Regional or local use of other calendars and the cultural and religious practices that accompany them continue. In Latin America, local cultures continue to observe traditions according to their own calendars. Israel, China, India and other countries continue to celebrate the new year on different dates.

January 1: the first day of the Gregorian calendar year in most countries.

As the world is divided into multiple time zones, the new year will gradually develop globally as the new year begins. The first time zone to greet the new year to the west of the international date line is in the lane islands, part of Kiribati's country, 14 hours earlier than UTC. All other time zones were one to 25 hours later than the previous day (31 December); in American Samoa and midway, it is still 11 p.m. on 30 December. This is the latest place for people to celebrate the new year. However, the uninhabited remote areas of the United States, Howland island and Baker Island, were designated as time zones 12 hours after UTC time zone, the last place on earth to see the arrival of January 1. These small coral islands lie between Hawaii and Australia, about 1000 miles west of the Rhine islands. This is because the international date change line is a combination of local time zone arrangements that meanders across the Pacific Ocean, keeping each region in the closest or largest or most convenient political and economic region in time. When I saw the new year in Howland Island, it was 2 a.m. on January 2, in the line islands of Kiribati.