Leap year most years that are multiples of 4 are leap years. In each leap year, the month of February has 29 days instead of 28. Adding one extra day in the calendar every four years compensates for the fact that a period of 365 days is shorter than a tropical year by almost 6 hours. Some exceptions to this basic rule are required since the duration of a tropical year is slightly less than 365.25 days. The Gregorian reform modified the Julian calendar's scheme of leap years as follows: Over a period of four centuries, the accumulated error of adding a
Jewish Talmudic Calendar the previous evening, at the time of sunset, when three mediums sized stars appear. Practically it begins from 6:00 p.m. (18:00) Jerusalem time (16:00 Universal Time). A day is divided into 24 hours, each with 1080 parts (halakim). Thus each minute is composed of 18 halakim; each halakim is 3.33 seconds. There are twelve months in a common year, and thirteen months in a leap year. The New Years Day (Rosh Hashana) is Tishri 1. The months are 30 days and 29 days in turns. A regular common year is 354 days; while a regular leap year is 384 days