<P> The Hebrew lunar year is about eleven days shorter than the solar year and uses the 19 - year Metonic cycle to bring it into line with the solar year, with the addition of an intercalary month every two or three years, for a total of seven times per 19 years . Even with this intercalation, the average Hebrew calendar year is longer by about 6 minutes and 40 seconds than the current mean tropical year, so that every 216 years the Hebrew calendar will fall a day behind the current mean tropical year; and about every 231 years it will fall a day behind the mean Gregorian calendar year . </P> <P> The era used since the Middle Ages is the Anno Mundi epoch (Latin for "in the year of the world"; Hebrew: לבריאת העולם ‎, "from the creation of the world"). As with Anno Domini (A.D. or AD), the words or abbreviation for Anno Mundi (A.M. or AM) for the era should properly precede the date rather than follow it . </P> <P> AM 5779 began at sunset on 9 September 2018 and will end at sunset on 29 September 2019 . </P> <P> The Jewish day is of no fixed length . The Jewish day is modeled on the reference to "...there was evening and there was morning ..." in the creation account in the first chapter of Genesis . Based on the classic rabbinic interpretation of this text, a day in the rabbinic Hebrew calendar runs from sunset (start of "the evening") to the next sunset . Halachically, a day ends and a new one starts when three stars are visible in the sky . The time between true sunset and the time when the three stars are visible (known as' tzait ha'kochavim') is known as' bein hashmashot', and there are differences of opinion as to which day it falls into for some uses . This may be relevant, for example, in determining the date of birth of a child born during that gap . </P>

When is the new year according to the hebrew calendar