Solar Hijri calendar

The Solar Hijri calendar^[a] is the official calendar of Iran. It is a solar calendar and is the one Iranian calendar that is the most similar to the Gregorian calendar, being based on the Earth's orbit around the Sun. It begins on the March equinox as determined by the astronomical calculation for the Iran Standard Time meridian (52.5°E, UTC+03:30) and has years of 365 or 366 days. It is sometimes also called the Shamsi calendar and Khorshidi calendar. It is abbreviated as SH, HS or, sometimes as AHSh, while the lunar Hijri calendar (commonly known in the West as the 'Islamic calendar', although both calendars are Islamic) is usually abbreviated as AH. The solar Hijri calendar predominates in Shia Islam whereas the lunar Hijri calendar predominates in Sunni Islam.

For the lunar Hijri calendar used to date Islamic holidays and events, see Islamic calendar. For the Late Ottoman-era solar calendar, see Rumi calendar. For a succession of Iranian solar calendars, see Iranian calendars.

The first day of the Solar Hijri calendar was the day of the spring equinox, March 18, 622 CE. The calendar is named the "Hijri calendar" because that was the year that Mohammed is believed to have left from Mecca to Medina, which event is referred to as the Hijrah. This year is generally considered by Muslims as the first year of Islam.

The ancient Iranian Solar calendar is one of the oldest calendars in the world, as well as the most accurate solar calendar in use today. Since the calendar uses astronomical calculation for determining the vernal equinox, it has no intrinsic error.^[2][3][4][5] It is older than the lunar Hijri calendar used by the majority of Muslims (known in the West as the Islamic calendar); though they both count from the Hijrah.^[6][7] The solar Hijri calendar uses solar years and is calculated based on the "year of the Hijrah," and the lunar Hijri calendar is based on lunar months, and dates from the presumed actual "day of the Hijrah".

Each of the twelve months of the Hijri calendar corresponds with a zodiac sign, and in Afghanistan the names of the zodiacal signs were used for the months;^[b] elsewhere the month names are the same as in the Zoroastrian calendar. The first six months have 31 days, the next five have 30 days, and the last month has 29 days in common years but 30 days in leap years.

The ancient Iranian New Year's Day, which is called Nowruz, always falls on the March equinox. Nowruz is celebrated by communities in a wide range of countries from the Balkans to Mongolia. Currently the Solar Hijri calendar is officially used only in Iran.

A Solar Hijri calendar of year 1383 SH showing the second month of Ordibehesht (thus April–May 2004; see conversion table below). The months' name comes from the Avestan word for Asha.

Structure

Epochal date

The calendar's epoch (first year) corresponds to the Hijrah in 622 CE, which is the same as the epoch of the Lunar Hijri calendar but as it is a solar calendar, the two calendars' year numbers do not coincide with each other and are slowly drifting apart, being about 43 years apart as of 2023.

Days per month

The first six months (Farvardin–Shahrivar) have 31 days, the next five (Mehr–Bahman) have 30 days, and the last month (Esfand) has 29 days in common years or 30 days in leap years. This is a simplification of the Jalali calendar, in which the commencement of the month is tied to the sun's passage from one zodiacal sign to the next. The sun is travelling fastest through the signs in early January (Dey) and slowest in early July (Tir). The current time between the March and September equinoxes is about 186 days and 10 hours, the opposite duration about 178 days, 20 hours, due to the eccentricity of Earth's orbit. (These times will change slowly due to precession of the Earth's apsides, becoming inverted after around 11 500 years.)

Leap years

The Iranian Solar calendar produces a five-year leap year interval after about every seven four-year leap year intervals.^{[citation needed]} It usually follows a 33-year subcycle with occasional interruptions by a single 29-year subcycle. The reason for this behaviour is (as explained above) that it tracks the observed vernal equinox.

Some predictive algorithms had been suggested, but were inaccurate due to confusion between the average tropical year (365.2422 days) and the mean interval between spring equinoxes (365.2424 days). These algorithms are not generally used (see Accuracy).

New Year's Day

The Ancient Iranian Solar calendar year begins at the start of spring in the Northern Hemisphere: on the midnight in the interval between the two consecutive solar noons that includes the instant of the March equinox.^{[citation needed]} Hence, the first mid-day is on the last day of one calendar year, and the second mid-day is on the first day (Nowruz) of the next year.

Months

Order	Days	Persian (Iran)		Dari (Afghanistan)		Tajik		Kurdish (Iran)		Pashto		Azerbaijani		Gregorian range	Zodiac sign
		Native Script	Romanized	Native Script	Romanized	Native Script	Romanized	Sorani Script	Kurmanji Script	Native Script	Romanized	Arabic Script	Latin Script
01	31	فروردین	Farvardin	حمل	Hamal	Фарвардин / Ҳамал	Farvardin / Hamal	خاکەلێوە	Xakelêwe	وری	Wray	آغلار-گۆلر	Ağlar-gülər	March – April	♈️Aries
02	31	اردیبهشت	Ordibehesht	ثور	Sawr	Урдибиҳишт / Савр	Urdibihisht / Savr	گوڵان	Gullan (Banemer)	غويی	Ǧwayáy	گۆلن	Gülən	April – May	♉️ Taurus
03	31	خرداد	Khordad	جوزا	Jawzā	Хурдод / Ҷавзо	Khurdod / Javzo	جۆزەردان	Cozerdan	غبرګولی	Ǧbargoláy	قؽزاران	Qızaran	May – June	♊️ Gemini
04	31	تیر	Tir	سرطان	Saraṭān	Тир / Саратон	Tir / Saraton	پووشپەڕ	Pûşper	چنګاښ	Čungā́x̌	قوْرا بیشیرن	Qora bişirən	June – July	♋️ Cancer
05	31	مرداد / امرداد	Mordad / Amordad	اسد	Asad	Мурдод / Асад	Murdod / Asad	گەلاوێژ	Gelawêj	زمری	Zmaráy	قۇیرۇق دوْغان	Quyruq doğan	July – August	♌️ Leo
06	31	شهریور	Shahrivar	سنبله	Sonbola	Шаҳривар / Сунбула	Shahrivar / Sunbula	خەرمانان	Xermanan	وږی	Wáǵay	زۇمار	Zumar	August – September	♍️ Virgo
07	30	مهر	Mehr	میزان	Mizān	Меҳр / Мизон	Mehr / Mizon	ڕەزبەر	Rezber	تله	Tә́la	خزل	Xəzəl	September – October	♎️ Libra
08	30	آبان	Aban	عقرب	ʿAqrab	Обон / Ақраб	Obon / Aqrab	گەڵاڕێزان	Xezellwer (Gelarêzan)	لړم	Laṛám	قؽروْو	Qırov	October – November	♏️ Scorpio
09	30	آذر	Azar	قوس	Qaws	Озар / Қавс	Ozar / Qavs	سەرماوەز	Sermawez	ليندۍ	Lindә́i	آذر	Azər	November – December	♐️ Sagittarius
10	30	دی	Dey	جدی	Jadi	Дай / Ҷадӣ	Day / Jadī	بەفرانبار	Befranbar	مرغومی	Marǧúmay	چیلله	Çillə	December – January	♑️ Capricorn
11	30	بهمن	Bahman	دلو	Dalvæ	Баҳман / Далв	Bahman / Dalv	ڕێبەندان	Rêbendan	سلواغه	Salwāǧá	دوْندۇران	Donduran	January – February	♒️ Aquarius
12	29/30	اسفند / اسپند	Esfand / Espand	حوت	Hūt	Исфанд / Ҳут	Isfand / Hut	ڕەشەمە	Reşeme	كب	Kab	بایرام	Bayram	February – March	♓️ Pisces

The first day of the calendar year, Nowruz ("New Day"), is the greatest festival of the year in Iran, Afghanistan, and some surrounding historically Persian-influenced regions. The celebration is filled with many festivities and runs a course of 13 days, the last day of which is called siz-dah bedar ("13 to outdoor").

The Dari (Afghan Persian) month names are the signs of Zodiac. They were used in Iran in the early 20th century when the solar calendar was being used.

Days of the week

In the Iranian calendar, every week begins on Saturday and ends on Friday. The names of the days of the week are as follows: shanbeh, yekshanbeh, doshanbeh, seshanbeh, chahārshanbeh, panjshanbeh and jom'eh. Yek, do, se, chahār, and panj are the Persian words for the numbers one to five. The name for Friday, jom'eh, comes from Arabic (جمعة.) Jom'eh is sometimes referred to by the native Persian name, ādineh [ɒːdiːne] (آدینه). In some Islamic countries, like Iran and Afghanistan, Friday is the weekly holiday.

Calculating the day of the week is easy, using an anchor date. One good such date is Sunday, 1 Farvardin 1372, which equals 21 March 1993. Assuming the 33-year cycle approximation, move back by one weekday to jump ahead by one 33-year cycle. Similarly, to jump back by one 33-year cycle, move ahead by one weekday.

As in the Gregorian calendar, dates move forward exactly one day of the week with each passing year, except if there is an intervening leap day when they move two days. The anchor date 1 Farvardin 1372 is chosen so that its 4th, 8th, ..., 32nd anniversaries come immediately after leap days, yet the anchor date itself does not immediately follow a leap day.

Current usage

As of 2024 CE, the only official user of the calendar is Iran.

Iran

A Persian-language contract published in Tehran on 14 April 1910, which used Lunar Hijri calendar

On 21 February 1911, the second Iranian parliament adopted as the official calendar of Iran the Jalali sidereal calendar with months bearing the names of the twelve constellations of the zodiac and the years named for the animals of the duodecennial cycle; it remained in use until 1925.^[1] The present Iranian calendar was legally adopted on 31 March 1925, under the early Pahlavi dynasty. The law said that the first day of the year should be the first day of spring in "the true solar year", "as it has been" ever so. It also fixed the number of days in each month, which previously varied by year with the sidereal zodiac. It revived the ancient Persian names, which are still used. It also set the epoch to the Hijrah. It also deprecated the 12-year cycles of the Chinese-Uighur calendar, which were not officially sanctioned but were commonly used.

In 1975, Iranian scholars discovered that this solar calendar was in use as early as the Achaemenid Era.^[1] Therefore, the Pahlavi Government, under the orders of Shah Mohammad Reza Pahlavi, changed the epoch of the calendar to be the first year of the reign of Cyrus the Great, rather than the Hijrah of Muhammad, a change that birthed the Shahanshahi calendar^[c]. Overnight, the year number changed from 1354 to 2534. The change lasted until the Iranian revolution in 1979, at which time the new Iranian government reverted the epoch to the Hijrah.^[9]

Afghanistan

Afghanistan legally adopted the official Jalali calendar in 1922^[1] but with different month names. Afghanistan uses Arabic names of the zodiacal signs; for example, the Saur Revolution in 1978 took place in the second month of the Solar Hijri calendar (Persian Ordibehesht; Saur is named after Taurus). The Solar Hijri calendar has been until recently the official calendar of the government of Afghanistan,^[10] and all national holidays and administrative issues were fixed according to the Solar Hijri calendar.

However, the Taliban imposed the lunar Hijri calendar in Afghanistan during both periods of their rule. Under the Taliban's first rule from 1996 to 2001, the lunar Hijri calendar was imposed, thus changing the year overnight from 1375 to 1417.^[11] With effect from 1 Muharram 1444 AH (8 Mordad 1401 SH; 30 July 2022 CE) (the Islamic New Year of the lunar Hijri calendar), the Taliban once again imposed the lunar calendar. Thus the year number once again leaped forward, this time from 1401 to 1444.^[12]

Tajikistan

Tajikistan does not use the Solar Hijri calendar and has never done so, despite being part of the Persian-speaking world. The country does, however, celebrate Nowruz, although the official New Year's Day in Tajikistan is 1 January in the Gregorian calendar,^[13] which is also the case in other non-Persian speaking Iranian or Turkic communities ranging from Eastern Europe to Western China. The name of Tajikistan's capital, Dushanbe, is taken from the Solar Hijri calendar and translates to "Monday" in Persian.^[14]

Comparison with Gregorian calendar

The Solar Hijri year begins about 21 March of each Gregorian year and ends about 20 March of the next year. To convert the Solar Hijri year into the equivalent Gregorian year add 621 or 622 years to the Solar Hijri year depending on whether the Solar Hijri year has or has not begun.

Correspondence of Solar Hijri and Gregorian calendars (Solar Hijri leap years are marked*)^[15]

33-year cycle[16]	Solar Hijri year	Gregorian year	Solar Hijri year	Gregorian year
1	1354*	21 March 1975 – 20 March 1976	1387*	20 March 2008 – 20 March 2009
2	1355	21 March 1976 – 20 March 1977	1388	21 March 2009 – 20 March 2010
3	1356	21 March 1977 – 20 March 1978	1389	21 March 2010 – 20 March 2011
4	1357	21 March 1978 – 20 March 1979	1390	21 March 2011 – 19 March 2012
5	1358*	21 March 1979 – 20 March 1980	1391*	20 March 2012 – 20 March 2013
6	1359	21 March 1980 – 20 March 1981	1392	21 March 2013 – 20 March 2014
7	1360	21 March 1981 – 20 March 1982	1393	21 March 2014 – 20 March 2015
8	1361	21 March 1982 – 20 March 1983	1394	21 March 2015 – 19 March 2016
9	1362*	21 March 1983 – 20 March 1984	1395*	20 March 2016 – 20 March 2017
10	1363	21 March 1984 – 20 March 1985	1396	21 March 2017 – 20 March 2018
11	1364	21 March 1985 – 20 March 1986	1397	21 March 2018 – 20 March 2019
12	1365	21 March 1986 – 20 March 1987	1398	21 March 2019 – 19 March 2020
13	1366*	21 March 1987 – 20 March 1988	1399*	20 March 2020 – 20 March 2021
14	1367	21 March 1988 – 20 March 1989	1400	21 March 2021 – 20 March 2022
15	1368	21 March 1989 – 20 March 1990	1401	21 March 2022 – 20 March 2023
16	1369	21 March 1990 – 20 March 1991	1402	21 March 2023 – 19 March 2024
17	1370*	21 March 1991 – 20 March 1992	1403*	20 March 2024 – 20 March 2025
18	1371	21 March 1992 – 20 March 1993	1404	21 March 2025 – 20 March 2026
19	1372	21 March 1993 – 20 March 1994	1405	21 March 2026 – 20 March 2027
20	1373	21 March 1994 – 20 March 1995	1406	21 March 2027 – 19 March 2028
21	1374	21 March 1995 – 19 March 1996	1407	20 March 2028 – 19 March 2029
22	1375*	20 March 1996 – 20 March 1997	1408*	20 March 2029 – 20 March 2030
23	1376	21 March 1997 – 20 March 1998	1409	21 March 2030 – 20 March 2031
24	1377	21 March 1998 – 20 March 1999	1410	21 March 2031 – 19 March 2032
25	1378	21 March 1999 – 19 March 2000	1411	20 March 2032 – 19 March 2033
26	1379*	20 March 2000 – 20 March 2001	1412*	20 March 2033 – 20 March 2034
27	1380	21 March 2001 – 20 March 2002	1413	21 March 2034 – 20 March 2035
28	1381	21 March 2002 – 20 March 2003	1414	21 March 2035 – 19 March 2036
29	1382	21 March 2003 – 19 March 2004	1415	20 March 2036 – 19 March 2037
30	1383*	20 March 2004 – 20 March 2005	1416*	20 March 2037 – 20 March 2038
31	1384	21 March 2005 – 20 March 2006	1417	21 March 2038 – 20 March 2039
32	1385	21 March 2006 – 20 March 2007	1418	21 March 2039 – 19 March 2040
33	1386	21 March 2007 – 19 March 2008	1419	20 March 2040 – 19 March 2041

Accuracy

Its determination of the start of each year is astronomically accurate year-to-year as opposed to the more fixed Gregorian or Common Era calendar which, averaged out, has the same year length, achieving the same accuracy (a differently patterned calendar of 365 days for three consecutive years plus an extra day in the next year, save for three exceptions to the latter in a 400-year cycle). The start of the year and its number of days remain fixed to one of the two equinoxes, the astronomically important days when day and night each have the same duration. It results in less variability of all celestial bodies when comparing a specific calendar date from one year to others.^[17]

Birashk leap year algorithm

Iranian mathematician Ahmad Birashk (1907–2002) proposed an alternative means of determining leap years. Birashk's book came out in 1993, and his algorithm was based on the same apparently erroneous presumptions as used by Zabih Behruz in his book from 1952.^[17] Birashk's technique avoids the need to determine the moment of the astronomical equinox, replacing it with a very complex leap year structure. Years are grouped into cycles which begin with four normal years, after which every fourth subsequent year in the cycle is a leap year. Cycles are grouped into grand cycles of either 128 years (composed of cycles of 29, 33, 33, and 33 years) or 132 years, containing cycles of 29, 33, 33, and 37 years. A great grand cycle is composed of 21 consecutive 128-year grand cycles and a final 132 grand cycle, for a total of 2820 years. The pattern of normal and leap years which began in 1925, will not repeat until the year 4745.

The accuracy of the system proposed by Birashk and other recent authors, such as Zabih Behruz, has been thoroughly refuted and shown to be less precise than the traditional 33-year cycle.^[17]

Each 2820-year great grand cycle proposed by Birashk contains 2137 normal years of 365 days and 683 leap years of 366 days, with the average year length over the great grand cycle of 365.24219852. This average is just 0.00000026 (2.6×10⁻⁷) of a day shorter than Newcomb's value for the mean tropical year of 365.24219878 days, but differs considerably more from the mean vernal equinox year of 365.242362 days, which means that the new year, intended to fall on the vernal equinox, would drift by half a day over the course of a cycle.^[17]

See also

• Iran portal
• Afghanistan portal

• List of observances set by the Solar Hijri calendar
• Arabic names of Gregorian months
• Assyrian calendar
• Babylonian calendar
• Hebrew calendar
• Indian calendar
• Iranian calendars
• Islamic calendar
• Jalali calendar
• Pre-Islamic Arabian calendar
• Rumi calendar
• Zoroastrian calendar

Notes

1. Persian: گاه‌شماری خورشیدی, romanized: Gâhšomâri-ye Xoršidi; Pashto: لمريز لېږدیز کلیز, romanized: lmaríz legdíz kalíz; Kurdish: ڕۆژژمێری کۆچیی ھەتاوی, romanized: Salnameya Koçberiyê; also called in some English sources as the Iranian Solar calendar^[1]
2. Since 1 Muharam 1444 AH (30 July 2022 CE), this calendar is no longer used by the government of Afghanistan, after its switch to the Lunar Hijri calendar.^[8]
3. Persian: گاه‌شماری شاهنشاهی, romanized: Gâhšomâri-ye Šâhanšâhi; not to be confused with the Zoroastrian Shahanshahi calendar

References

1. ""Calendars" in Encyclopaedia Iranica". Iranicaonline.org. Retrieved 11 August 2012.
2. "دقیق ترین تقویم جهان، هدیه خیام به ایرانیان" [The most accurate calendar in the world, Khayyam's gift to Iranians] (in Persian). BBC Persian. Retrieved 6 July 2013.
3. "پيمانه کردن سال و ماه از ديرباز تا کنون در گفتگو با دکتر ايرج ملک پور" [Measuring the year and month for a long time until now in a conversation with Dr. Iraj Malekpour] (in Persian). BBC Persian. Retrieved 6 July 2013.
4. "پژوهش‌های ایرانی | پاسداشت گاهشماری ایرانی" [Iranian Studies & # 124; Preservation of the Iranian calendar]. Ghiasabadi.com. 3 November 2005. Retrieved 6 July 2013.
5. "پژوهش‌های ایرانی | گاهشماری تقویم جلالی" [Iranian Studies & # 124; Glory Calendar Timeline]. Ghiasabadi.com. 25 September 2007. Retrieved 6 July 2013.
6. Shaikh, Fazlur Rehman (2001). Chronology of Prophetic Events. London: Ta-Ha Publishers Ltd. pp. 51–52.
7. Marom, Roy (Fall 2017). "Approaches to the Research of Early Islam: The Hijrah in Western Historiography". Jamma'a. 23: vii.
8. "Taliban Changes Solar Year to Hijri Lunar Calendar". Hasht-e Subh Daily. 26 March 2022. Archived from the original on 4 September 2022. Retrieved 4 September 2022.
9. Molavi, Afshin; Mawlawī, Afšīn (2002). Persian Pilgrimages by Afshin Molavi. ISBN 9780393051193. Retrieved 11 August 2012.
10. Gannon, Kathy. "The AP Interview: Taliban pledge all girls in schools soon". The Washington Post. Retrieved 15 January 2022.
11. Conant, Eve (30 November 2021). "Why Afghans Don't Know Their Ages". NBC News. Archived from the original on 12 November 2020. Retrieved 19 October 2022.
12. "Taliban Changes Solar Year to Hijri Lunar Calendar". Hasht-e Subh Daily. 26 March 2022. Archived from the original on 4 September 2022. Retrieved 4 September 2022.
13. Debbie Nevins (2020). Tajikistan. Cavendish Square Publishing. p. 118.
14. WERYHO, JAN W. (1994). "Tajiki Persian as a Europeanised Oriental Language". Islamic Studies. 33 (2/3): 341–373. JSTOR 20840172 – via JSTOR.
15. Holger Oertel (30 May 2009). "Persian calendar by Holger Oertel". Ortelius.de. Archived from the original on 16 July 2012. Retrieved 11 August 2012.
16. The Persian calendar for 3000 years, (Kazimierz M Borkowski), Earth, Moon, and Planets, 74 (1996), No. 3, pp 223–230. Available at .
17. M. Heydari-Malayeri, A concise review of the Iranian calendar, Paris Observatory.

External links

• How the leap years are calculated
• Meaning of the names of the months in the Persian Calendar

Online calendars and converters

• An online Persian (shamsi)/Gregorian/Islamic (hijri) date converter on http://www.iranchamber.com
• Online Persian Calendar and converter from parstimes.com
• Online Persian Calendar from aaahoo portal
• GFDL Afghan Calendar with Gregorian, Hejrah-e shamsi and Hejrah-e qamari dates

Programming

• GPL Iranian Calendar in JavaScript Archived 13 February 2012 at the Wayback Machine
• System.Globalization.PersianCalendar class documentation in MSDN Library (The implementation of Persian Calendar in Microsoft .NET Framework 2.0)
• Persian Zodiac a free, open source AIR application. Archived 2 November 2014 at the Wayback Machine