New Year's Day 2026はいつ？

New Year's Day on 1 January is the most universally observed public holiday on Earth. The Gregorian calendar — which sets 1 January as the start of the year — is the world's most widely used civil calendar. It was introduced by Pope Gregory XIII in 1582 as a reform of the Julian calendar, and its January 1 new year was gradually adopted across Europe and then globally over the following centuries.

The celebration of a new year is far older than the Gregorian calendar. Ancient Mesopotamians celebrated Akitu in spring; the Romans observed Kalends of January from 153 BCE; many cultures have their own new year dates tied to astronomical or agricultural events. The Islamic, Hebrew, Chinese, Ethiopian, and Persian calendars all have distinct new year celebrations on different dates.

Modern New Year's Eve celebrations — countdowns, fireworks, parties, and the singing of Auld Lang Syne — are largely a product of 20th-century media culture. New Year's Day itself is a statutory public holiday in virtually every country, and the 24-hour cycle of midnight fireworks — beginning in the Pacific and ending in the Americas — is one of the most globally shared moments of the year.