Hogmanay's New Year's Eve in Scotland's Gregorian calendar is December 31.
Hogmanay is the Scottish name for the final day of the year and for the celebrations surrounding the change into January 1. In modern Scotland, the principal evening of Hogmanay is therefore December 31, followed by New Year’s Day celebrations on January 1 and often a public holiday on January 2.
The historical background is more complicated because Scotland used the Julian calendar until 1600 and later adopted the Gregorian calendar in 1752. Calendar reforms changed the relationship between dates and seasons, but they did not change the modern civil date used for Hogmanay. The surviving name reflects Scottish language and custom rather than a separate calendar system.
Hogmanay is also sometimes confused with Burns Night, which falls on January 25 and celebrates Robert Burns, and with Hogmanay events that continue into January 1. The word can refer both to the night itself and to the wider festival period, while December 31 remains the canonical date.