Ayyám-i-Há refers to a period of four or five intercalary days in the Bahá'í calendar, where Bahá'ís celebrate the Festival of Ayyám-i-Há. The four or five days occur in between the 18th and 19th months of the calendar from February 26 to March 1 and allow for the Bahá'í calendar to be synchronized with the solar year with regular years of 365 days, and leap years of 366 days.