The Ethiopian calendar is unique in many respects, but the basis of its chronology is the Coptic calendar. There are thirty days in each standard month, and there are twelve such months in a year. There is also an intercalary "thirteenth month," (P̣agumen), which ordinarily consists of five days, and six in the case of a leap year. The Ethiopian leap year always precedes the Gregorian (Western) leap year. Thus, New Year's Day in the year following a leap year in the Ethiopian calendar will fall on the 12th of September not on the 11th, as it would usually.