User:Etewilak/Hebrew calendar

Types of years
The following are the 14 types of Hebrew calendar years:
 * I: Deficient common year beginning on Monday
 * II: Complete common year beginning on Monday
 * III: Regular common year beginning on Tuesday
 * IV: Regular common year beginning on Thursday
 * V: Complete common year beginning on Thursday
 * VI: Deficient common year beginning on Saturday
 * VII: Complete common year beginning on Saturday
 * VIII: Deficient embolismic year beginning on Monday
 * IX: Complete embolismic year beginning on Monday
 * X: Regular embolismic year beginning on Tuesday
 * XI: Deficient embolismic year beginning on Thursday
 * XII: Complete embolismic year beginning on Thursday
 * XIII: Deficient embolismic year beginning on Saturday
 * XIV: Complete embolismic year beginning on Saturday

Deficient, regular, and complete common years are 353, 354, and 355 days long, respectively; deficient, regular, and complete embolismic years are 383, 384, and 385 days long, respectively.

Common years

 * Tevet begins on Tuesday in a regular common year beginning on Thursday (type IV), a property that is not shared by other year types. In addition, Erev Pesach (14 Nisan) falls on Friday in a type IV year, the only common year with this property.
 * Erev Pesach falls on Saturday in a complete common year beginning on Thursday (type V) and deficient common year beginning on Saturday (type VI).

Embolismic years

 * A deficient embolismic year beginning on Monday (type VIII) is always preceded by a regular common year beginning on Thursday (type IV) and followed by a complete common year beginning on Saturday (type VII).
 * A complete embolismic year beginning on Monday (type IX) is always preceded by a regular common year beginning on Thursday (type IV). In fact, an embolismic year beginning on Monday, whether deficient or complete, is always preceded by a type IV year.
 * A regular embolismic year (type X) always begins on Tuesday. It is always followed by a complete common year beginning on Monday (type II).
 * A deficient embolismic year beginning on Thursday (type XI) is always preceded by a complete common year beginning on Saturday (type VII) and followed by a regular common year beginning on Tuesday (type III). Tevet begins on Monday in a type XI year, a property that is not shared by other year types. In addition, Erev Pesach falls on Saturday in a type XI year, the only embolismic year with this property.
 * A complete embolismic year beginning on Thursday (type XII) is always followed by a regular common year beginning on Thursday (type IV).
 * A deficient embolismic year beginning on Saturday (type XIII) is always preceded by a complete common year beginning on Monday (type II).

Common years

 * There were no complete common years beginning on Thursday from 5664 to 5733.
 * The last complete common year beginning on Thursday occurred in 5754. The next one will occur in 5785.
 * There were no complete common (355-day) Hebrew years from 5771 to 5779.

Embolismic years

 * The last regular embolismic year, which always begins on Tuesday, occurred in 5755. The next one will occur in 5782.
 * The last deficient embolismic year beginning on Monday occurred in 5749. The next one will occur in 5790.
 * The last deficient embolismic year beginning on Thursday occurred in 5768. The next one will occur in 5812.
 * The last deficient embolismic year beginning on Saturday occurred in 5757. The next one will occur in 5784.
 * The four embolismic years in the 5770’s decade (5771, 5774, 5776, and 5779) were all complete (385 days long). The first two began on Thursday; the last two began on Monday.

Certain days of the Hebrew calendar

 * In the 5770’s, Erev Pesach (14 Nisan) never fell on Wednesday.
 * In 5780, Erev Pesach fell on Wednesday for the first time since 5769.
 * In 5781, Erev Pesach will fall on Saturday for the first time since 5768.