The Badí calendar is based on the solar year of 365 days, 5
hours, and 50 odd minutes. The year consists of 19 months of 19 days each (i.e.
361 days), with the addition of four extra days (five in a leap year). The Báb
did not specifically define the place for the intercalary days in the new
calendar. The Kitáb-i-Aqdas resolves this question by assigning the “excess”
days a fixed position in the calendar immediately preceding the month of ‘Alá,
the period of fasting.
- The Universal House of Justice (The 'Notes' section of
the Kitab-i-Aqdas)
