Happy Lunar New (Leap) Year
January 22, 2023 marks the beginning of new year across East Asia based on lunar calendars (based on the phases of the Moon) and lunisolar (which also considers the Earth's path around the Sun). Lunar New Year falls on the day following the second second new moon after the winter solstice.
Because the lunar phases (lunation) don't line up very well with the Gregorian calender we use every day, Lunar New Year fluctuates from year to year. Lunar New Year fell on February 1 in 2022.
This Year of the Rabbit, or year 4720 on the Chinese calendar, is also a leap year.
Like the Gregorian Calendar, the lunisolar Chinese calendar also doesn't lineup very well the tropical year (the time it takes Earth to complete a trip around the Sun, or 365.2422 days) making it necessary to insert intercalary time into the calendar.
While the Gregorian calendar adds a day to the end of February about every four years, the Chinese calendar adds a month to the end of the year about every 3 (lunisolar) years. If there are 13, then the next new year is delayed until the next new moon. This is why the next Lunar New Year wont be until February 10, 2024.
Each month in the Chinese calendar contains a principal term as the Sun reaches a longitude which is a multiple of 30 degrees. Leap months help ensure that each year contains only 12 principal terms. Leap months, like the one that will be inserted this year, do not contain a principal term.
