| Because of the roughly eleven-day
difference between twelve lunar
months and one solar year, the year
lengths of the Hebrew calendar vary
in a repeating 19-year Metonic cycle
of 235 lunar months, with an
intercalary lunar month added every
two or three years, for a total of 7
times per 19 years. Seasonal
references in the Hebrew calendar
reflect its development in the
region east of the Mediterranean Sea
and the times and climate of the
Northern Hemisphere. With respect to
the present-day mean solar year, the
Hebrew calendar's year is longer by
about 6 minutes and 25+25/57
seconds, meaning that every 224
years, the Hebrew calendar will fall
a full day behind the modern fixed
solar year, and about every 231
years it will fall a full day behind
the Gregorian calendar year. This is
due to the 0.6 second discrepancy
between the Calendric "Molad" (lunar
conjunction interval), which is
fixed by Jewish Law,[4] and the
actual mean lunar conjunction
interval, which itself is slowly
changing over time.[5]
History
Biblical period
Mosaic pavement of a zodiac in the
6th century synagogue at Beit Alpha,
Israel. 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,
Genesis 7:11, 8:4, :5, :13, :14) it
is implied that the months are
thirty days long.[6] 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 (first; literally
"Spring", originally this probably
meant "the ripening of barley"), Ziv
(second; literally "Light"), Ethanim
(seventh; literally "Strong" in
plural, perhaps referring to strong
rains), and Bul (eighth). All of
these are Canaanite names, and at
least two are Phoenician (Northern
Canaanite).
The Torah includes a number of
commandments related to the keeping
of the calendar and the lunar cycle,
including the first commandment the
Jewish people received as a nation,
to determine the new moon: Exodus
12:2 states, "This month [Nissan] is
for you the first of months."
Numbers 10:10 refers to the
observation of the new moon, "Also
in the day of your gladness, and in
your appointed seasons, and in your
new moons, ye shall blow with the
trumpets over your
burnt-offerings,"[7] and Numbers
28:11 commands, "And in your new
moons ye shall present a
burnt-offering unto the LORD: two
young bullocks, and one ram, seven
he-lambs of the first year without
blemish."[8] Deuteronomy 16:1 refers
to a specific month: "Observe the
month of Abib, and keep the passover
unto the LORD thy God; for in the
month of Abib the LORD thy God
brought thee forth out of Egypt by
night."[9]
However, the adoption of a purely
lunar calendar cycle would have
resulted in the starting date of the
first month of the lunar year
progressively drifting away from the
Spring, due to the difference in
length between twelve lunar months
and a solar year. Since the Torah
specifies not only the significance
of the lunar month, but also
mandates that the dates of certain
festivals correspond to a given
season of the year, it is to be
inferred that a system of
reconciling the lunar months and the
solar year was in use. The Bible
does not directly mention the
addition of an "embolismic" or
intercalary month that would prevent
the drifting of the calendar year,
however, it is hinted that the first
month was started only following the
ripening of barley, and according to
some traditions, if the barley had
not yet ripened, another monthly
cycle would be interjected after the
"last month" (Adar), before the
first month of the year was
announced.
Thus, if Adar was over and the
barley was not yet ripe, an
additional month, "Adar II" was
observed before Nisan. During such
leap years Adar I (or Adar Aleph —
"first Adar") is actually considered
to be the extra month, and has 30
days. Adar II (or Adar Bet — "second
Adar") is the "real" Adar, and has
the usual 29 days. For this reason,
during a leap year, holidays such as
Purim are observed in Adar II, not
Adar I. Later, a mathematical system
was developed to replace the
observational method.
Babylonian exile and nomenclature
Detail of the Ishtar Gate of
Babylon, dating from the era of the
Babylonian captivity.During the
Babylonian exile, which started in
586 BCE, Jews adopted Babylonian
names for the months, which have
continued to be used to this day.
The Babylonian calendar also used a
lunisolar calendar, derived from the
Sumerian calendar. The Hebrew
calendar follows the common
seven-day weekly cycle, with the
Hebrew names for the weekdays 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 (Hebrew: 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 Ḥamishi (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
In Hebrew, the word "Shabbat" (שַׁבָּת)
can also mean "(Talmudic) week",[10]
so that in ritual liturgy a phrase
like "Yom Reviʻi bəShabbat" means
"the fourth day in the week".[11]
Hebrew names and romanized
transliteration may somewhat differ,
as they do for כסלו / Kislev or
חשוון / Marheshvan: the Hebrew words
shown here are those commonly
indicated e.g. in newspapers.
Hebrew
names of the months with their
Babylonian analogs
| Number |
Hebrew |
Academy |
Common/Other |
Length |
Babylonian
analog |
Notes |
|
1 |
נִיסָן |
Nisan |
Nissan |
30 days |
Nisanu |
called Aviv
and Nisan in the Tanakh |
|
2 |
אִיָּר / אייר |
Iyyar |
Iyar |
29 days |
Ayaru |
called Ziv in
the Tanakh |
|
3 |
סִיוָן /
סיוון |
Siwan |
Sivan |
30 days |
Simanu |
|
|
4 |
תַּמּוּז |
Tammuz |
Tamuz |
29 days |
Du'uzu |
|
|
5 |
אָב |
Av |
Ab |
30 days |
Abu |
|
|
6 |
אֱלוּל |
Elul |
Elul |
29 days |
Ululu |
|
|
7 |
תִּשׁרִי |
Tishri |
Tishrei |
30 days |
Tashritu |
called
Eitanim in the Tanakh.
Modern first month, Rosh Hashana
is celebrated in Tishrei. |
|
8 |
מַרְחֶשְׁוָן
/ מרחשוון |
Marẖeshwan |
Marcheshvan |
29 or 30 days |
Arakhsamna |
often
shortened to Cheshvan; called
Bul in the Tanakh |
|
9 |
כִּסְלֵו /
כסלוו |
Kislew |
Kislev,
Chisleu |
30 or 29 days |
Kislimu |
also spelled
Chislev |
|
10 |
טֵבֵת |
Tevet |
Tebeth |
29 days |
Tebetu |
|
|
11 |
שְׁבָט |
Shevat |
Shvat, Shebat |
30 days |
Shabatu |
|
|
12* |
אֲדָר א׳ |
Adar I* |
|
30 days |
Adaru |
*Only
in leap years |
|
12 / 13* |
אדר / אדר ב׳ |
Adar / Adar
II* |
|
29 days |
Second Temple era, c.
518 BCE - 70 CE
|
