In a 52-week year, weeks are distributed in repeating cycles of 4 and 5, resulting in 13 weeks per quarter. The cycle specifies the number of weeks in each of the three months used.
4-4-5 Calendar—The first month of the quarter has four weeks, the second, four weeks, and the third, five weeks.
5-4-4 Calendar—The first month of the quarter has five weeks, the second, four weeks, and the third, four weeks.
4-5-4 Calendar—The first month of the quarter has four weeks, the second, five weeks, and the third, four weeks.