Relative hour (Hebrew singular: shaʿah zǝmanit / שעה זמנית; plural: shaʿot - zǝmaniyot / שעות זמניות), sometimes called halachic hour, seasonal hour and variable hour, is a term used in rabbinic Jewish law that assigns 12 hours to each day and 12 hours to each night, all throughout the year. A relative hour has no fixed length in absolute time, but changes with the length of daylight each day - depending on summer (when the days are long and the nights are short), and in winter (when the days are short and the nights are long). Even so, in all seasons a day is always divided into 12 hours, and a night is always divided into 12 hours, which invariably makes for a longer hour or a shorter hour.[1][2] At Mediterranean latitude, one hour can be about 45 minutes at the winter solstice, and 75 minutes at summer solstice.[3] All of the hours mentioned by the Sages in either the Mishnah or Talmud, or in other rabbinic writings, refer strictly to relative hours.[4][5]

Another feature of this ancient practice is that, unlike the standard modern 12-hour clock that assigns 12 o'clock pm for noon time, in the ancient Jewish tradition noon time was always the sixth hour of the day, whereas the first hour began with the break of dawn according to many Halachic authorities,[6] and with sunrise according to others.[7] Midnight (12:00 am local official clock time) was also the sixth hour of the night, which, depending on summer or winter, can come before or after 12:00 am local official clock time, whereas the first hour of the night always begins at sunset or when the first three stars appeared in the night sky.

During the Spring (באחד בתקופת ניסן‎) and Autumnal (באחד בתקופת תשרי‎) equinox (around 20 March and 23 September), the length of a day and night are equal.[8] However, even during the summer solstice and winter solstice when the length of the day and the length of the night are at their greatest disparity, both day and night are always divided into 12 hours.

Jewish tradition

Rabbi Pinchas said in the name of Rabbi Abba bar Pappa: One star is certainly day; two [stars] is a doubtful case; three [stars] is certainly night.[9]

In old times, the hour was detected by observation of the position of the sun,[10] or when the first three stars appeared in the night sky. During the first six hours of the day, the sun is seen in the eastern sky. At the sixth hour, the sun is always at its zenith in the sky, meaning, it is either directly overhead, or parallel (depending on the hemisphere).[11] Those persons living in the Northern Hemisphere, the sun at noon time will appear overhead slightly towards the south, whereas for those living in the Southern Hemisphere, the sun at noon time will appear overhead slightly towards the north (an exception being in the tropics, the sun can sometimes be directly overhead). From the 6th and a half hour to the 12th hour, the sun inclines towards the west, until it sets. The conclusion of a day at the end of twilight may slightly vary in minutes from place to place, depending on the elevation and the terrain.[12] Typically, nightfall ushers in more quickly in the low-lying valleys, than it does on a high mountaintop.[13]

There are two major opinions how to calculate these times:

In the Modern Age of astral science and of precise astronomical calculations, it is now possible to determine the length of the ever-changing hour by simple mathematics. To determine the length of each relative hour, one needs but simply know two variables: (a) the precise time of sunrise, and (b) the precise time of sunset. Since according to the first opinion, the day begins approximately 72 minutes before sunrise and ends approximately 72 minutes after sunset (and according to the variant understanding of this opinion, ends approximately 13½ or 18 minutes after sunset), or begins at sunrise and ends at sunrise according to the second opinion, by collecting the total number of minutes in any given day and dividing the total number of minutes by 12, the quotient that one is left with is the number of minutes to each hour. In summer months, when the days are long, the length of each hour during daytime can be quite long depending on one's latitude, whereas the length of each hour during nighttime can be quite short again depending on one's latitude. It should also be noted that according to those opinions that the 72 minutes are computed according to 16.1 degrees, the further one goes from the equator, the longer it will get, such that in northern latitudes it could become 2 hours or longer.

Practical bearing

In Jewish Halacha, the practical bearing of this teaching is reflected in many halachic practices. For example, according to Jewish law, the morning recitation of Kriyat Shema must be made between slightly before sunrise and the end of the third hour of the day, a time that actually fluctuates on the standard 12-hour clock, depending on the time of year.[41] Its application is also used in determining the time of the Morning Prayer, which must be recited between sunrise until the end of the fourth hour,[42] but post facto can be said until noon time,[43] and which times will vary if one were to rely solely on the dials of the standard 12-hour clock, depending on the seasons.

On the eve of Passover, chametz can only be eaten until the end of the fourth-hour of the day, and must be disposed of by the end of the fifth hour.[44]

In Jewish tradition, prayers were usually offered at the time of the daily whole-burnt offerings.[45] The historian, Josephus, writing about the daily whole-burnt offering, says that it was offered twice each day, in the morning and about the ninth hour.[46] The Mishnah, a compendium of Jewish oral laws compiled in the late 2nd-century CE, says of the morning daily offering that it was offered in the fourth hour,[47] but says of the late afternoon offering: "The daily whole-burnt offering was slaughtered at a half after the eighth hour, and offered up at a half after the ninth hour."[48] Elsewhere, when describing the slaughter of the Passover offerings on the eve of Passover (the 14th day of the lunar month Nisan), Josephus writes: "...their feast which is called the Passover, when they slay their sacrifices, from the ninth hour to the eleventh, etc." (roughly corresponding to 3 o'clock pm to 5 o'clock pm).[49] Conversely, the Mishnah states that on the eve of Passover the daily whole-burnt offering was slaughtered at a half past the seventh hour, and offered up at a half past the eighth hour.[48]

See also

Further reading


  1. ^ R. Moses b. Maimon Responsa, ed. Jehoshua Blau, Rubin Mass Ltd. Publishers, Jerusalem 1989, vol. 1, responsum # 134
  2. ^ Mishnah - with a Commentary of Rabbi Moses ben Maimon (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Berakhot 1:5 (p. 33); Questions and Responsa of Rabbi Moses ben Maimon (ed. Joshua Blau), vol. 1, Rubin Mass publishers: Jerusalem 1989, responsum # 134 (pp. 251–255); Yaakov de Castro, `Erekh Leḥem (Orach Chaim §233:2)
  3. ^ Laurence, Ray (2006). Roman Pompeii: Space and Society. Routledge. pp. 104–112. ISBN 978-1-134-76899-8. Retrieved 24 December 2019.
  4. ^ Mishnah - with a Commentary of Rabbi Moses ben Maimon (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Berakhot 1:5 (p. 33), who wrote: "Be apprised that all of the hours that are mentioned throughout all the Mishnah are none other than relative hours, and the word relative has the connotation of those hours wherein there are twelve in the daytime, as also at night."
  5. ^ Questions and Responsa of Rabbi Moses ben Maimon (ed. Joshua Blau), vol. 1, Rubin Mass publishers: Jerusalem 1989, responsum # 134 (p. 252)
  6. ^ Magen Avraham §58:1, §233:3 of R. Avraham Gombiner; Maimonides' commentary on Mishnah Megillah 2:4; the Responsa Terumat HaDeshen, responsum # 1 of R. Israel Isserlein; the Levush §267 of R. Mordecai Yoffe; Minchat Kohen (Mevoh Shemesh 2:6) of R. Abraham Cohen Pimentel, in the name of Tosefot Ha-Ramban (Nachmanides) and R. Shlomo ben Aderet (Rashba); Bayit Chadash §431 of R. Joel Sirkis; Turei Zahav §433 of R. David HaLevi Segal; Pri Chadash §433 of R. Hezekiah da Silva; Eliyahu Rabbah 58:2 of R. Elijah Spira; Mizbe’ach Adamah 4a of R. Mordechai Chaim Meyuchas; Mikra'ei Kodesh 158b by R. Baruch Gigi; Mateh Yehuda §433 of R. Yehudah Ayash; the Responsa Hayim Sha'al 2:38 (70) of R. Chaim Yosef David Azulai; Tov Ayin 18:38 of R. Alter Yechiel Naiman; Chayei Adam 21:3, 27:1 of R. Avraham Danzig; Kitzur Shulhan Arukh 17:1 of R. Shlomo Ganzfried, Chesed La'alafim 58:5 of R. Eliezer Papo; Shiltei ha-Gibborim 58:3 of Joshua Boaz ben Simon Baruch; Rav Poalim (Orach Chaim 2:2); Shalmei Tzibbur 93c of R. Yisrael Ya'akov Algazi, among others. Rabbi Yechiel Michel Tukachinsky in Sefer Eretz Yisrael (p. 18:3) has written that the custom of the Land of Israel is to follow the Magen Avraham and only under extenuating circumstances may one rely on the Vilna Gaon.
  7. ^ None as the opinion of the Vilna Gaon, as cited in Bi'urei ha-Gra ("Elucidations of the Gra") §459:2, but also the opinion of Rabbi Hai Gaon and many other authorities cited in the next section.
  8. ^ Jerusalem Talmud (Berakhot 1:1)
  9. ^ Jerusalem Talmud (Berakhot 1:1 [2b])
  10. ^ Sefer Ravid ha-Zahav of Rabbi David Mishreqi (Mizrachi), ed. Shimon Giat, Betar-Ilit 2002, Responsa Ravid Ha-Zahav, responsum # 13, s.v. ונהירנא (p. 182)
  11. ^ Babylonian Talmud, Pesahim 12b; 11b
  12. ^ Israel Meir Kagan, Mishnah Berura on Shulhan Arukh (Orah Hayyim 261:2:23), otherwise known as the time it takes to walk "three quarters of a biblical mile."
  13. ^ In the Babylonian Talmud (Shabbat 118b) we read: Rabbi Jose has said: “Let my portion be with those who usher in the Sabbath day [at its outset] in Tiberias, and with those who dismiss the Sabbath day [at its recess] in Sepphoris.” This has been explained by Aaron Mordechai Freedman (editor of the 1987 Soncino edition of Tractate Shabbath): "In Tiberias, which was situated in a valley, the Sabbath commenced rather earlier, whilst in Sepphoris, which was on a mountain, it terminated rather later than elsewhere." (v. Hebrew-English Edition of the Babylonian Talmud, Tractate Shabbath, Soncino edition, London 1987, s.v. Shabbath 118b, note (b)3).

    Freedman's description of twilight being, literally, an oscillating physical reality dependent upon one's location is supported by Rabbi Joseph ibn Migash (1077–1141) [Responsa of R. Joseph ibn Migash, responsum # 45] and by Rabbi David ben Zimra (c. 1479–1573) [Responsa of Rabbi David ben Zimra, book I, responsum # 76], as also by Rabbi Hayyim Eliezer, the son of Isaac ben Moses of Vienna (13th century), who also compiled a book called "Or Zarua" (responsum # 186). Apparently, there is a local phenomenon relating to light emanating from fixed stars in the sky, and their becoming visible once a certain level of darkness has enveloped the land. Rashi, however, differs in view, whose opinion is supported also by Rabbi Menachem Meiri (1249–1306) Langa's Edition, p. 460, and Rabbi Nissim ben Jacob (990–1062), and who all thought that twilight was a fixed time for all, but that the people of Tiberias and Sepphoris were merely stringent in their religious practices, the one group welcoming the Sabbath early, while the other departing from it as late as possible.
  14. ^ Tosefot and Tosefot Rash mi-Shantz Pesachim 11b and Tosefot Sanhedrin 41b.
  15. ^ Berakhot 2a
  16. ^ Berakhot 3a and 27a,
  17. ^ Berakhot 26
  18. ^ Responsa 1
  19. ^ OC 431:1
  20. ^ 266
  21. ^ Kuntres de-ve shimshei.
  22. ^ This is the opinion of Rabbi Nathan Adler (brought by Rabbi Yehosef Schwartz in Divrei Yosef 59b, who himself rejects this opinion), Ben Ish Hai (Year 1 Vayakehel 4:8), Rabbi Mordecai Karmi (Maamar Mordechai 233:2) and others.
  23. ^ Mishnah - with a Commentary of Rabbi Moses ben Maimon (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Berakhot 1:5 (p. 33); Megillah 2:4 (p. 232)
  24. ^ Responsa of Rabbi David ben Zimra, Book 4, Warsaw 1882 (reprinted), s.v. responsum # 1353 (282)
  25. ^ Babylonian Talmud, Shabbat 34b–35a; Chaim Yosef David Azulai, Birkei Yosef (Orah Hayyim, § 261:1), Levorno 1774, citing the author of Ginat Weradim, who wrote: "The world has it as a practice in all the Diaspora communities of Israel [to follow the opinion of] the Geonim" (i.e. with respect to the time of bayn ha-shemashot (twilight; nightfall), so that immediately following sunset begins the time known as bayn ha-shemashot, which is the time it takes to walk three quarters of a biblical mile). The opinion of Rabbi Chaim Azulai comes to counter a variant opinion that is also found in the Talmud (Pesahim 94a), where it states that a man is able to walk four mil between sunset and nightfall, an opinion not as widely accepted.
  26. ^ Yosef Karo, Shulhan Arukh (Orah Hayyim § 459:2)
  27. ^ Divrei Yosef 59b
  28. ^ Tukatzinsky, Yechiel Michel (1928). Sefer Bein ha-Shemashos (in Hebrew). Jerusalem. pp. 97-98. OCLC 233065543. The opinion of our Rabbi, the Vilna Gaon, as well as of many other poskim, is that in all the halachic matters touching on the hours [of the day], we reckon [the day] from sunset until sunset, such as the latest time [one is required to recite] Kiryat Shema, [being] a quarter of the day (a third of the hours), and the latest time of the [morning] prayer, [being] a third of the day (four hours), and the latest time [permitted in] eating leaven on the eve of Passover, [being] a third of the day, and the burning of leaven in another relative hour – all [hours being reckoned] from sunrise until sunset. ...The practice is to be stringent in accordance with the Vilna Gaon's method when it comes to the latest time [in which a person recites] Kiryat Shema, and [says] the [morning] prayer, and when it comes to eating and burning the leaven [on the eve of Passover].((cite book)): CS1 maint: location missing publisher (link)
  29. ^ Shiurei Tziyon, Siman 35.
  30. ^ Minchas Yitzchak, Volume 4, Siman 53
  31. ^ Mishnas Rabbi Aharan, Volume 1, Siman 2.
  32. ^ Yoma 28b
  33. ^ "Zmanim Terms". Kehillat Israel. Archived from the original on 5 June 2015. Retrieved 4 December 2012.
  34. ^ Brought in Shu"t Mahara"m Alshaker 96
  35. ^ Siddur Rav Saadya Gaon page 26
  36. ^ Brought it Mordechai Berakhot #90
  37. ^ Beginning of 4th chapter of Berakhot.
  38. ^ Teshuva in Peer Hador 44
  39. ^ Beginning of 4th chapter of Berakhot.
  40. ^ OC 233:1
  41. ^ Mishnah - with a Commentary of Rabbi Moses ben Maimon (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Berakhot 1:5 (p. 33)
  42. ^ Yosef Karo, Shulhan Arukh (Orah Hayyim § 89:1)
  43. ^ Mishnah, Berakhot 4:1 (Maimonides, Mishne Torah, Hil. Tefillah 3:1)
  44. ^ Mishnah (Pesahim 1:4)
  45. ^ Rabbeinu Hananel's Commentary on Tractate Berakhot (ed. David Metzger),Jerusalem 1990, s.v. Berakhot 26a (p. 51)
  46. ^ Josephus, Antiquities (xiv.iv.§ 3)
  47. ^ Mishnah, Eduyot 6:1
  48. ^ a b The Mishnah (ed. Herbert Danby), Oxford University Press: Oxford 1977, s.v. Pesahim 5:1, p. 141
  49. ^ Josephus, Wars (vi.ix.§ 3)