Home > Calendar > Leap Years in the Persian Calendar

Leap Years in the Persian Calendar

As an observational calendar based on the timing of the astronomical seasons, the Solar Hijri calendar does not have mathematical rules to determine leap years. However, there is a rule-based version that achieves a similarly high degree of accuracy.

Iran flag waving in the wind above the skyline of Tehran lit by the orange glow of sunset.

Iranian flag over Tehran, Iran.

The Iranian flag flying over Tehran, Iran. The Solar Hijri calendar officially used in Iran and Afghanistan is one of the most accurate calendar systems worldwide.

©bigstockphoto.com/Borna

Seasons Determine Leap Years

The Solar Hijri calendar year begins and ends with the vernal equinox. Like in the Gregorian calendar, there are common years with 365 days and leap years with 366 days.

The distribution of leap years, however, is not determined by mathematical rules, but by the timing of the equinoxes. This makes the Solar Hijri calendar, which is the official calendar in Iran and Afghanistan, one of the world's most accurate calendar systems.

Read more about the Solar Hijri calendar

Rule-Based Alternative

Several proposals for mathematical leap year rules have been made to approximate the inherent accuracy of the Solar Hijri calendar without relying solely on astronomical observations. With a deviation from the solar year of only 1 day in about 110,000 years, the most widely accepted set of rules are about as accurate as the observational calendar:

  • Group years into periods of 2820 years each. The current 2820-year cycle began in 1096 CE.
  • Divide the periods into 88 cycles of varying lengths, following this pattern for the first 84 cycles:
    29 years, 33 years, 33 years, 33 years,
    29 years, 33 years, 33 years, 33 years...
  • The final cycle in each 2820-year period is 37 years long; the pattern for the final 4 cycles is:
    29 years, 33 years, 33 years, 37 years.
  • Number the years in each cycle starting with 0. For instance, the year 1096 CE is year 0, 1097 CE is year 1, 1098 CE is year 2, and so on.
  • All years whose ordinal numbers are divisible by 4 are leap years. The first year of each cycle (ordinal number 0) is a common year.

Topics: Leap Year, Calendar

Persian Leap Years:

Year 1395 is a leap year. It began on March 20, 2016 and ends on March 20, 2017.
The next leap years are:

Persian YearGregorian Year
13992020 / 2021
14042025 / 2026
14082029 / 2030
14122033 / 2034
14162037 / 2038
Advertising

Alternative Leap Years

  1. Bahá'í Calendar Leap Year
  2. Chinese Calendar Leap Year
  3. Ethiopian Calendar Leap Year
  4. Hindu Calendar Leap Year
  5. Persian Calendar Leap Year
  6. Islamic Calendar Leap Year
  7. Jewish Calendar Leap Year

Leap Years in Other Calendars


You might also like

Lotus Temple, Bahai house of worship in New Delhi, India.

Bahá'í Leap Year

The Bahá'í leap year occurs when five extra days are added between the last two months of the calendar. Leap years usually occur every four years. more

The Church of St. George in Lalibela, Ethiopia.

The Ethiopian Calendar

The Ethiopian calendar is quite similar to the Julian calendar which was the predecessor to the Gregorian calendar most countries use today. more

Leap Day Birthdays

When do “leaplings” celebrate their birthdays – every year or only during leap years? more

Equinox and solstice illustration.

A Year Is Never 365 Days

The definition of a tropical year, also known as a solar year, astronomical year, or equinoctial year, is the time it takes the Earth to complete a full orbit around the Sun, and it is approximately 365.242189 days long. more