SOLAR HIJRI CALENDAR

PART OF THIS SERIES, "TRACKING TIME: BEHIND THE CLOCK AND CALENDAR"

Author: Ken Klark L. Flores

Photo: Kara Grizzle / Pinterest

Introduction

The Solar Hijri calendar, also known as the Persian or Iranian calendar, is a solar calendar used as the official calendar in Iran and Afghanistan. It is based on the Earth's orbit around the sun, with a new year beginning on the vernal equinox (Nowruz), which falls between March 19 and 21. The calendar counts years from the Hijra, the migration of the Prophet Muhammad in 622 CE, and is known for its high accuracy (Research Guides: Nowruz: Calendars, 2025).

Origins

Its origin is tied to ancient Persian timekeeping traditions but uses the Hijra (Prophet Muhammad's migration to Medina in 622 CE) as its epoch, much like the separate lunar Hijri calendar. The Earliest forms of Iranian time reckoning date back to the second millennium BCE. The first version of the modern solar calendar was the highly accurate Jalali calendar, developed in the 11th century by a group of astronomers including the Persian polymath Omar Khayyam. This calendar was known for its precision, based on astronomical observation of the solar year and the vernal equinox (Nowruz) (The Persian Calendar (Solar Hijri Calendar) – Welcome to Iran, n.d.)

The modern Solar Hijri calendar was formally adopted as the official civil calendar of Iran in 1925. The law stipulated that the first day of the year must be the spring equinox and brought back the ancient Persian month names.  It is widely believed that 'Abd al-Ghaffār Khān Najm al-Dawlah was the first to use the phrase "solar hijri" and calculate a solar calendar from the year of the Prophet's migration. 

System

Unlike the purely lunar Islamic calendar used for religious purposes in many other Muslim countries, the Solar Hijri calendar tracks the solar year.

The year begins precisely at the astronomical moment of the vernal equinox (spring equinox), which is determined by precise astronomical observations from the meridian of Tehran. This makes it more accurate than the rule-based Gregorian calendar, which accumulates an error of one day every 3,236 years (compared to the Solar Hijri's error of one day in approximately 110,000 years). A year typically has 365 days, with 366 in a leap year. The first six months have 31 days, the next five have 30 days, and the last month has 29 days (or 30 in a leap year) (Yau, 2025).

The months are: Farvardin, Ordibehesht, Khordad, Tir, Mordad, Shahrivar, Mehr, Aban, Azar, Dey, Bahman, and Esfand, corresponding to zodiac signs and starting with the vernal equinox (around March 21st) (Hub, 2025).

The current year according to the Solar Hijri calendar is SH 1404, while in the lunar Hijri calendar it is AH 1447. 

Reference:

Research Guides: Nowruz: Calendars. (2025). Emory.edu. https://guides.libraries.emory.edu/c.php?g=1457269&p=10835095

‌The Persian Calendar (Solar Hijri Calendar) – Welcome to Iran. (n.d.). https://welcometoiran.com/persian-calendar-solar-hijri/

‌Yau, H. (2025, November 8). The Persian Solar Hijri Calendar. Time.now. https://time.now/articles/persian-solar-hijri-calendar-time-accuracy-and-culture/

‌Hub, L. (2025, August 26). Months in Farsi – complete guide with pronunciation for beginners. Language Learning with Preply Blog. https://preply.com/en/blog/months-in-farsi/

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