Korean New Year is the first day of the Korean lunar calendar. It is one of the most significant traditional Korean holidays. The celebration lasts three days: the day before Korean New Year day, Korean New Year day itself, and the day after Korean New Year day.
Korean New Year generally falls on the day of the second new moon after winter solstice, unless there is a very rare intercalary eleventh or twelfth month in the lead-up to the New Year. In such a case, the New Year falls on the day of the third new moon after the solstice; the next occurrence of this will be in 2033.
Korean New Year is generally the same day as Chinese New Year except when new moon occurs between 15:00 UTC (Korean midnight) and 16:00 UTC (Chinese midnight). In such case (on average once every 24 years), new moon happens on the "next day" in Korea compared to China, and Korean New Year will be one day after Chinese New Year.