This is what we found on Wikipedia regarding the New Year's Eve Terrace Party:

New Year's Eve in the Gregorian calendar refers to the evening—or commonly the entire day—of the last day of the year: 31 December. In many countries, New Year's Eve is celebrated with dancing, eating, drinking, and watching or lighting fireworks. Many Christians attend a watchnight service to mark the occasion. New Year's Eve celebrations generally continue into New Year's Day, 1 January, past midnight.

The local time zone determines the advent of the New Year; the first places to welcome the New Year are west of the International Date Line: the Line Islands (part of Kiribati), Samoa and Tonga, in the Pacific Ocean. In contrast, American Samoa, Baker Island and Howland Island (part of the United States Minor Outlying Islands) are among the last.