Zoroastrian Calendar

Every one of the calendar's thirty days carries the name of a divinity. Ahura Mazda himself opens the month, the six Amesha Spentas and a run of Yazatas fill out the rest, and the twelve months are named from the same roster, so twelve of the thirty day names recur as month names and a day can share its name with the month it falls in. When it does, the coincidence is kept as a festival, most famously Mihragan, when the day Mihr meets the month Mihr in the autumn. Structurally the year is plain: twelve months of thirty days each, closed by five epagomenal Gatha days named for the five hymns of Zoroaster himself, giving three hundred sixty five days with, in the ancient reckoning, no leap day at all. That omission is the reason three distinct versions of the calendar exist today rather than one.

The Shahanshahi, "Imperial," calendar has run uncorrected since late antiquity and has drifted roughly a month against the true solar year; the Qadimi, "Ancient," calendar differs from it by one further month because some communities inserted a correction in the medieval period that others did not; and the Fasli calendar, adopted by reformers in the twentieth century, adds a leap day on the Gregorian pattern specifically to keep Nowruz pinned to the spring equinox. The three are not variants of a settled question but three live positions, and which one a given community keeps is a marker of its own history.

The calendar is not a museum piece. It sets living religious practice today across the communities that use it, Zoroastrians in Iran and the Parsi communities of India and Pakistan chief among them, and the split between the Shahanshahi, Qadimi and Fasli tracks is a genuinely present disagreement rather than a settled historical footnote, since it means different Zoroastrian communities can keep Nowruz, the new year, and Mihragan on different Gregorian dates in the same year depending on which calendar their community follows.

Traditionalist Parsis in India have generally kept the Shahanshahi or Qadimi reckoning for religious observance even where Fasli has been adopted for civil convenience elsewhere, and reform movements that pushed for the Fasli calendar in the early twentieth century did so explicitly to restore the seasonal accuracy the older calendars had lost through centuries without a leap day.

The five Gatha days at the year's end are still kept as a period of reflection and charity before Nowruz, echoing the hinge role Ayyam-i-Ha plays in the unrelated Baha'i calendar, and Zoroastrian households still time major rites of passage, including initiation into the sacred cord and shirt, by the calendar's month and day names rather than by the civil date alone. Which version of the calendar a family or fire temple follows is, in practice, still a marker of communal identity and migration history among Zoroastrians today.