Berber calendar has 28 days. The only slight discrepancy lies in that the extra day in leap years is not usually added at the end of February, but at the end of the year. This means that the beginning of the year (the first day of "yennayer") corresponds to the 14th day of January in the Gregorian calendar, which coincides with the offset accumulated during the centuries between astronomical dates and the Julian calendar. In addition to the subdivision by months, within the traditional agricultural calendar there are other partitions, by "seasons" or by "strong periods", characterized by particular festivals and celebrations.
Leap year lunar months containing 29 or 30 days, generally in alternating order. However, the tabular Islamic calendar used by Islamic astronomers during the Middle Ages and still used by some Muslims does have a regular leap day added to the last month of the lunar year in 11 years of a 30-year cycle. This additional day is found at the end of the last month, Dhu 'l-Hijja, which is also the month of the Hajj. The Hijri-Shamsi calendar, also adopted by the Ahmadiyya Muslim Community, is based on solar calculations and is similar to the Gregorian calendar in its structure with