On the Gregorian calendar, what date is New Year's Eve?

On the Gregorian calendar, New Year's Eve is December 31. It is the final day of the calendar year, leading into New Year's Day on January 1.

The Gregorian calendar was introduced by Pope Gregory XIII in 1582 to correct accumulated inaccuracies in the older Julian calendar. It gradually became the civil calendar used in most of the world, although some communities and countries also observe other calendar systems.

New Year's Eve can mean the entire date or, more narrowly, the evening of December 31. Celebrations often continue past midnight, so the countdown begins on December 31 but finishes on January 1. The date should not be confused with Christmas Day, December 25, or New Year's Day, January 1.

The moment the new year arrives depends on local time zones. Kiribati's Line Islands are among the first inhabited places to celebrate, while American Samoa is among the last.