In practice, a day is added to the 8th month ( Marcheshvan) or subtracted from the 9th month ( Kislev). These alterations are designed to prevent Rosh Hashana and other holidays from falling on certain days of the week. In addition to these regular ( kesidrah) year lengths, both common and leap years can be a day shorter ( cheserah or deficient year with 353/383 days) or a day longer ( shlemah or complete year with 355/385 days). Months with uneven numbers usually have 30 days, while months with even numbers have 29 days. Leap years have 13 months and are 384 days long. Regular common years have 12 months with a total of 354 days. Calendar Structure Months in the Jewish Calendar Month NamesĪ year in the Hebrew calendar can be 353, 354, 355, 383, 384, or 385 days long. In comparison with the timing of the astronomical seasons, it is off by 1 day every 216 years. The Hebrew calendar is a comparatively imprecise system in terms of reflecting the duration of a solar year, which is the time it takes Earth to complete a full orbit around the Sun. Featuring a body of complex regulations, exceptions, and mathematical rules, it is also designed to satisfy a number of requirements conveyed in the Jewish Holy Scripture.
Jewish time reckoning is lunisolar, which means that the calendar keeps in sync with the natural cycles of both the Sun and the Moon.
