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About Time in Iran

In Farrokhi, One Share of Qanat Water Lasted Seven and a Half Minutes

In many Iranian oases, water ownership was historically measured less by how many liters a farmer received than by how long the entire flow of a qanat belonged to that farmer. The method turned time into a property right.

Farrokhi, an oasis settlement in the Biabanak region, preserves an unusually precise example. Encyclopaedia Iranica records a local unit called the pangun, related to the Persian fenjan, equal there to the volume of qanat water flowing for seven and a half minutes. Water rights returned according to a ten-day irrigation cycle with named positions in the local calendar.

A nearby oasis used the same principle but not the same clock. At Mehrajān, one pangun represented twelve minutes of qanat flow, and the irrigation roster repeated every twenty days. Some days in that cycle were named after proprietors, while others were associated directly with water allocation.

The contrast is important. There was no universal Iranian irrigation minute imposed on every village. Each qanat community could develop its own timetable according to water supply, landholding and inherited rights. What mattered was that everyone accepted the relationship between a measured interval and a share of flowing water.

Across Iran, division by time became far more common than division by measured volume. The full discharge of a qanat passed successively from one user to the next according to a roster. Traditionally, a clepsydra or water clock could determine when one share ended and another began. In a few places sundials survived into the twentieth century before battery-powered watches increasingly replaced both.

Night complicated the schedule. Irrigating after dark reduced evaporation, making a nocturnal water share potentially more valuable than the same duration during the heat of day. Some communities therefore alternated daytime and nighttime turns or developed intricate rotation rules so that the same owners did not permanently receive the most advantageous hours.

The result was a hydrological society organized through time. A mirab, or water distributor, supervised access, disputes and transitions between users. The clock did not merely describe when irrigation happened. It helped define who legally and socially possessed the water at that moment.

For a Few Autumn Weeks, the Saffron Workday Begins Before Sunrise

In Khorasan, one of the most valuable harvests of the year begins while fields are still dark. Saffron flowers are short-lived, and the timing of collection affects the quality of the stigmas that become the spice.

Agricultural research from Iran places the main Khorasan flowering period broadly in October and November, with the precise onset influenced strongly by the timing of the first irrigation and by weather. A field may flower for only about fifteen to twenty-five days, with activity concentrated around a much shorter peak.

Harvesting is repeated every morning because individual flowers deteriorate quickly after opening. Studies of Iranian saffron production report that farmers generally prefer to pick before sunrise, while petals are still closed or only beginning to open. Exposure to heat, sunlight and wind can reduce quality and make handling the delicate stigmas more difficult.

The short biological window creates an intense labor calendar. Flowers that emerge overnight cannot simply be left until a more convenient day. Workers move through the fields at dawn, collect flowers by hand, and then separate the stigmas manually. Processing has to follow harvesting closely because storing intact flowers for too long also changes product quality.

Experimental work with Iranian saffron ecotypes shows how compressed the cycle can be. In one multi-season study, flowering began about two weeks after irrigation and continued for roughly thirty days. Flowers were harvested every day before sunrise and processed repeatedly throughout the flowering period.

The sequence makes saffron a crop in which hour and season matter simultaneously. The annual harvest may occupy only a few weeks, but within those weeks each sunrise creates another deadline. A farmer who misses a day cannot recover exactly the same flowers later, because the plant has already moved into another biological stage.

A Water Clock Built in Yazd in 1324 Controlled 150 Ropes

Iranian water clocks were not confined to irrigation channels. In 1324, Khalil ibn Abu Bakr ibn Mohammad Amoli built a remarkable clock at the Rokniya madrasa in Yazd. Descriptions preserved from the fifteenth century show a machine that combined hydraulic power, mechanical motion, calendrical display and astronomy.

The main reservoir was a copper tank described as about twice the height of a man. It had to be filled with water each day. Water escaped through an opening and tube into a well below, causing the level in the tank to fall gradually.

A floating weight inside the tank was attached to a chain. That chain was connected to approximately 150 ropes, each working against its own wooden counterweight. As the water level dropped, the float moved and transmitted motion through this elaborate network.

The machine did much more than divide a day into hours. Historical descriptions say it indicated days, months and years and worked with several different calendrical systems, including lunar and solar reckonings. It also represented the motion of stars.

That combination is revealing because timekeeping, calendar calculation and astronomy were not separate technical problems. The position of celestial bodies helped define the calendar, while a controlled mechanical process was needed to represent those cycles continuously between direct observations of the sky.

The Yazd device also shows the distance between a simple clepsydra and a sophisticated hydraulic clock. The same physical principle, water falling under gravity, could measure an irrigation turn in a village or operate a complex educational instrument with dozens of mechanical connections.

For Less Than Two and a Half Years, Iran Renumbered the Year by More Than a Millennium

Iranian civil time is unusual not only because the official calendar is solar, but because the state briefly changed the era from which its years were counted while leaving the structure of the months largely intact.

The modern Solar Hijri calendar became Iran's official calendar through legislation enacted on 31 March 1925. Its twelve months use Iranian names. The first six contain thirty-one days each, the next five contain thirty days, and Esfand has twenty-nine days in an ordinary year and thirty in a leap year.

The year is organized around the solar cycle rather than a drifting lunar year. Nowruz remains tied to the spring equinox, so the beginning of the Iranian year stays close to the same point in the seasons instead of moving through them.

A major legal experiment began in the 1970s. On 14 March 1975, legislation approved a new Shahanshahi era whose numbering was based on an assumed accession year of Cyrus the Great. When Nowruz arrived on 21 March 1976, official documents entered the year 2535 instead of 1355 in the Solar Hijri era.

The months themselves did not need to be rebuilt. Farvardin, Ordibehesht and the remaining month names continued in the same order, but the number attached to the year changed by more than a thousand years. Civil administration therefore altered historical epoch without changing the seasonal architecture of the calendar.

The experiment lasted less than two and a half years. On 27 August 1978, the government reverted to the Solar Hijri numbering. A document dated before and after that reform can therefore appear to jump between radically different centuries even though only days separate the two dates.

This episode is a reminder that a calendar contains several independent choices. The length of the year can remain solar, the month system can remain unchanged, and yet the number assigned to the year can be replaced almost instantly by law.

Iranian Daylight Saving Followed Farvardin and Shahrivar, Not a Sunday Rule

Iran's modern standard time is UTC+3:30, an offset that already distinguishes it from countries using whole hours. Its twentieth- and twenty-first-century clock history became more unusual when daylight saving was layered onto the Solar Hijri calendar.

The IANA Time Zone Database reconstructs Tehran Mean Time at about UTC+3:25:44 before national standardization. Current tzdata places the move to a UTC+3:30 standard in 1935. That rounded the historical longitude-based offset to a practical half-hour.

Daylight saving was introduced experimentally in the late 1970s, but the sequence was not stable. IANA's corrected historical data records DST in 1977, further changes during 1978 and 1979, and a temporary shift of the underlying standard offset to UTC+4 before Iran returned to UTC+3:30.

The later system was easier to understand if one used the Iranian calendar rather than the Gregorian one. During many years of modern DST, the forward transition occurred at the boundary associated with the beginning of the new Solar Hijri year, while the return occurred around the end of Shahrivar. In Gregorian dates, those transitions therefore appeared on March 21 or 22 and September 21 or 22 depending on the year.

This was fundamentally different from rules such as the last Sunday of March. A scheduling system that knew only Gregorian weekday formulas could not safely infer Iran's transition dates. Software needed rules based on the actual Iranian schedule, which is why revisions to historical and future Iran data repeatedly appeared in tzdb.

The final daylight-saving cycle ended in September 2022. Legislation repealed the law that had authorized seasonal clock changes and prohibited the government from moving official time in the same way from the beginning of the Iranian year 1402. IANA incorporated the change into its 2022b release, stating that Iran would no longer observe DST after 2022.

Since 2023, UTC+3:30 has remained fixed throughout the year. The interesting part of Iran's time-zone history is therefore not simply the half-hour offset. It is the way longitude, Solar Hijri dates, changing legislation and international software rules repeatedly interacted to determine what the clock in Tehran was supposed to show.

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