Structure
The Jewish calendar is a
lunisolar calendar, or
"fixed lunar year," based on
twelve
lunar months of
twenty-nine or thirty days,
with an
intercalary lunar month
added seven times every
nineteen years (once every
two to three years) to
synchronize the twelve lunar
cycles with the slightly
longer
solar year. Each Jewish
lunar month starts with the
new moon. Although
originally the new lunar
crescent had to be observed
and certified by witnesses,
the timing of the new moon
is now determined
mathematically.
Concurrently there is a
weekly cycle of seven days,
mirroring the seven-day
period of the
Book of Genesis in which
the world is created. The
names for the days of the
week, like those in the
Creation story, are simply
the
day number within the
week,
with
Shabbat being the
seventh day.
The Jewish day
always runs from sunset to
the next sunset; the formal
adjustments used to specify
a
standard time and
time zones are not
relevant to the Jewish
calendar.
The twelve regular months
are:
Nisan (30 days),
Iyar (29 days),
Sivan (30 days),
Tammuz (29 days),
Av (30 days),
Elul (29 days),
Tishrei (30 days),
Cheshvan (29 or 30
days),
Kislev (29 or 30 days),
Tevet (29 days),
Shevat (30 days), and
Adar (29 days). In the
leap years an additional
month, Adar I (30 days) is
added after Shevat, and the
regular Adar is referred to
as "Adar II".
The first month of the
festival year is Nisan. 15
Nisan is the start of the
festival of
Pesach, corresponding to
the
full moon of Nisan.
Pesach is a spring festival
associated with the barley
harvest,[3]
so the leap-month mentioned
above is intercalated
periodically to keep this
festival in the northern
hemisphere's spring season.
Since the adoption of a
fixed calendar,
intercalations in the Hebrew
calendar have been at fixed
points in a 19-year cycle.
Prior to this, the
intercalation was determined
empirically:
The year may be
intercalated on three
grounds: 'aviv [i.e.the
ripeness of barley],
fruits of trees, and the
equinox. On two of these
grounds it should be
intercalated, but not on
one of them alone.[4]
The Bible designates Nisan,
which it calls Aviv (Exodus
13:4), as the first
month of the year (Exodus
12:2). At the same time,
the season of the fall
Festival of Booths (Sukkoth),
is called "the end of the
year" (Exodus
23:16). The Sabbatical
year in which the land was
to lie fallow, necessarily
began at the time the winter
barley and winter wheat
would have been sown, in the
fall. The
Gezer calendar, an
Israelite or Canaanite
inscription ca. 900 BCE,
also begins in the fall.
Modern practice follows the
scheme described in the
Mishnah:
Rosh Hashanah, which
means "the head of the
year", and is celebrated in
the month of
Tishrei, is "the new
year for years." This is
when the numbered year
changes, and most Jews today
view Tishrei as the de
facto beginning of the
year.
Day
The Jewish
day is of no fixed
length.
The Jewish day is
modeled on the reference to
"...there was evening and
there was morning..."[5]
in the
Creation story.
Accordingly, it runs from
sunset (start of "the
evening") to the next
sunset. However, some apply
special rules at very high
latitudes when the sun
remains above or below the
horizon for longer than a
civil day.[6]
There is no clock in the
Jewish scheme, so that a
civil clock is used. Though
the civil clock incorporates
local adoptions of various
conventions such as
time zones,
standard times and
daylight saving, these
have no place in the Jewish
scheme. The civil clock is
used only as a reference
point - in expressions such
as: "Shabbat starts at ...".
The steady progression of
sunset around the world and
seasonal changes results in
gradual civil time changes
from one day to the next
based on observable
astronomical phenomena (the
sunset) and not on man-made
laws and conventions.
Instead of the
international date line
convention, there are
varying opinions as to where
the day changes. One opinion
uses the
antimeridian of
Jerusalem. (Jerusalem is
35°13’ east of the
prime meridian, so the
antimeridian is at 144°47'
W, passing through eastern
Alaska.) Other opinions
exist as well.[citation
needed]
Weeks
The Hebrew calendar follows
a seven-day
weekly cycle, which runs
concurrently but
independently of the monthly
and annual cycles. The names
for the days of the week are
simply the day number within
the week. In Hebrew, these
names may be abbreviated
using the
numerical value of the
Hebrew letters, for example
יום א׳ (Day 1, or Yom
Rishon (Hebrew:
יום ראשון):
-
Yom Rishon (יום ראשון),
abbreviated יום א׳ =
"first day" = Sunday
-
Yom Sheni (יום שני),
abbr. יום ב׳ = "second
day" = Monday
-
Yom Shlishi (יום שלישי),
abbr. יום ג׳ = "third
day" = Tuesday
-
Yom Reviʻi (יום רבעי),
abbr. יום ד׳ = "fourth
day" = Wednesday
-
Yom Chamishi (יום חמישי),
abbr. יום ה׳ = "fifth
day" = Thursday
-
Yom Shishi (יום ששי),
abbr. יום ו׳ = "sixth
day" = Friday
-
Yom Shabbat (יום שבת or
more usually שבת -
Shabbat), abbr. יום ש׳ =
"Sabbath day (Rest day)"
= Saturday
The names of the days of the
week are modeled on the
seven days mentioned in the
Creation story. For
example,
Genesis 1:5 "... And
there was evening and there
was morning, one day". "One
day" also translates to
"first day" or "day one".
Similarly, see
Genesis 1:8,
1:13,
1:19,
1:23,
1:31 and
2.2.
The Jewish
Shabbat has a special
place in the Jewish weekly
cycle. There are many
special rules which relate
to the Shabbat, discussed
more fully in the Talmudic
tractate "Shabbat".
In Hebrew, the word
"Shabbat" (שַׁבָּת) can also
mean "(Talmudic) week",[7]
so that in ritual liturgy a
phrase like "Yom Reviʻi
bəShabbat" means "the fourth
day in the week".[8]
Importance of lunar months
Num 10:10 stresses the
importance of the
new moon and
consequently lunar months,
"... in your new moons, ye
shall blow with the trumpets
over your burnt-offerings,"[9].
Similarly in
Num 28:11.
In his work
Mishneh Torah, of
1178, Maimonides included a
chapter "Sanctification of
the New Moon," in which he
discusses the calendrical
rules and their scriptural
basis. He notes,
"By how much does the
solar year exceed the
lunar year? By
approximately 11 days.
Therefore, whenever this
excess accumulates to
about 30 days, or a
little more or less, one
month is added and the
particular year is made
to consist of 13 months,
and this is the
so-called embolismic
(intercalated) year. For
the year could not
consist of twelve months
plus so-and-so many
days, since it is said:
throughout the months of
the year (Num
28:14), which
implies that we should
count the year by months
and not by days."[10]
Months
Biblical references to the
pre-Jewish calendar include
ten months identified by
number rather than by name.
In parts of the
Torah portion
Noach (Noah)
(specifically,
Gen 7:11,
Gen 8:4-5,
Gen 8:13-14) it is
implied that the months are
thirty days long.[11]
There is no indication as to
the total number of months
in the annual cycle.
In the parts of the
Tanakh (the
Hebrew Bible) prior to
the Babylonian exile, only
four months are named:
Aviv (12:2,
Exodus 13:4,
23:15,
34:18,
Deut. 16:1) (first;
literally "spring", which
originally probably meant
"the ripening of barley");
Ziv (1 Kings
6:1,
6:37) (second; literally
"light");
Ethanim (1 Kings
8:2) (seventh; literally
"strong" in plural, perhaps
referring to strong rains);
and
Bul (1 Kings
6:38) (eighth). All of
these are
Canaanite names, and at
least two are
Phoenician (Northern
Canaanite).[citation
needed]
According to the
Book of Exodus, the
first commandment the Jewish
people received as a nation
was to determine the
new moon:
Exodus 12:2 states,
"This month [Nisan] is for
you the first of months."
Deut 16:1 refers to a
specific month: "Observe the
month of Aviv (HE: spring),
and keep the passover unto
the LORD thy God; for in the
month of Aviv the LORD thy
God brought thee forth out
of Egypt by night."
During the
Babylonian exile, which
started in 586 BCE, Jews
adopted
Babylonian names for the
months, which are still in
use.
The
Babylonian calendar also
used a lunisolar calendar,
derived from the
Sumerian calendar, which
was similar in structure to
the Hebrew one.
Hebrew names and romanized
transliteration may somewhat
differ, as they do for חשוון
/ Marheshvan or כסלו
/ Kislev: the Hebrew words
shown here are those
commonly indicated e.g.
in newspapers. The
Syrian calendar used in
the
Levant countries shares
many of the same names for
months as the Hebrew
calendar, such as Nisan,
Iyyar, Tammuz, Ab, Elul,
Tishri, and Adar.
