Swedish calendar Julian calendar. An extra day was added to February in the leap year of 1712, thus giving it a unique 30-day length (February 30). In 1753, one year later than England and its colonies, Sweden introduced the Gregorian calendar. The leap of 11 days was accomplished in one step, with February 17 being followed by March 1. Easter was to be calculated according to the Easter rules of the Julian calendar from 1700 until 1739, but from 1700 to 1711, Easter Sunday was dated in the anomalous Swedish calendar, described above. In 1740, Sweden finally adopted the "improved calendar" already
Calendar year length of 365.25 days, and the Hebrew calendar has an average length of 365.2468 days. The Islamic calendar is a lunar calendar consisting of 12 months in a year of 354 or 355 days. The astronomer's mean tropical year, which is averaged over equinoxes and solstices, is currently 365.24219 days, slightly shorter than the average length of the year in most calendars, but the astronomer's value changes over time, so William Herschel's suggested correction to the Gregorian calendar may become unnecessary by the year 4000. The calendar year can be divided into four quarters, often abbreviated as Q1, Q2, Q3,