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.
Calendar as the week. Because the number of days in the "tropical year" is not a whole number, a solar calendar must have a different number of days in different years. This may be handled, for example, by adding an extra day in leap years. The same applies to months in a lunar calendar and also the number of months in a year in a lunisolar calendar. This is generally known as intercalation. Even if a calendar is solar, but not lunar, the year cannot be divided entirely into months that never vary in length. Cultures may define other units of