About Dadvah

Dadvah is a Persian calendar for Iranians who love Iran: its ancient cultures, its languages and its many peoples. It brings these ancient and beautiful threads together in one place, where the joys and sorrows, the struggles and triumphs of the Iranian nation are recorded, celebrated and remembered. It runs on the desktop, on the web and on the phone.

Exact dates

Nowruz begins on the day of the March equinox, if the equinox falls before noon in Tehran; otherwise on the next day. Dadvah computes it from NASA JPL's DE440 ephemeris rather than from an arithmetic rule, so leap years come out as the sky decides. The same engine runs in the apps and on this website.

Events, with sources

The calendar keeps the Persian festivals, the holy days of Iran's Zoroastrian, Christian, Jewish, Bahá’í, Mandaean, Hindu and Sikh communities, and the history of the Iranian people. Every event names the sources it was checked against, and where the historical record and an official calendar disagree, the record wins.

The name

Dadvah (said DUD-vah) is the Avestan daδuuah-, “the Creator”, a title of Ahura Mazda. It gave its name to Dey, the tenth month, which begins the morning after Yalda (Encyclopaedia Iranica, “Day”). From the first of Dey, after Yalda, the longest night of the year, the days grow longer: light begins to win against darkness. That turning is why this calendar carries the name.