Germanic calendar inspired by the Julian calendar, introduced a purely solar reckoning with a year having a fixed number of weeks (52 weeks or 364 days). This necessitated the introduction of "leap weeks" instead of Julian leap days. The old Icelandic calendar is not in official use any more, but some Icelandic holidays and annual feasts are still calculated from it. It has 12 months, of 30 days broken down into two groups of six often termed "winter months" and "summer months". The calendar is peculiar in that each month always start on the same day of week. This was achieved by
Calendar reform in advance). This calendar has 19 months of 19 days, with an extra 4 or 5 intercalary days added so that the year ends on the day before the next vernal equinox. Lunisolar calendars usually have 12 or 13 months of 29 or 30 days. Some propose to improve leap rules of existing calendars, such as the Hebrew calendar. The Rectified Hebrew calendar uses a more accurate leap cycle of 4366 months per 353-year cycle, with 130 leap years per cycle, and a progressively shorter "molad" interval, intended to replace the 19-year leap cycle and the constant "molad" interval of