Shahrivar — month 6 of the Persian year
The sixth month of the Solar Hijri year: Shahrivar in Iranian usage, Sunbula in Afghan usage, where it is also referred to as borj 6.
The month at a glance
- Month number
- 6
- In Iranian usage
- Shahrivar
- In Afghan usage
- Sunbula, or borj 6
- Length
- 31 days
- Gregorian window
- August 22 to September 23
This month shares its Afghan name with a zodiac sign. What the tradition carries for the sign is on the sign's own page; this page is about the month.
Two naming systems, one month
Month 6 of the Solar Hijri calendar is called Shahrivar in Iranian usage and Sunbula in Afghan usage. Both names refer to the same month of the same calendar. Neither is the real name and neither is a variant of the other; they are simply two systems of names in use for one set of months.
In Afghan usage the traditional borj names are the month names, and those names are the same words used for the zodiac signs. Alongside them runs a numbering convention: a month is commonly referred to by its number rather than its name. That is what borj 6 means. Someone asking which month borj 6 is, is asking about this month — Sunbula in Afghan usage, Shahrivar in Iranian usage.
Only the names differ. The month boundaries are the same, the month lengths are the same, and the leap rule is the same. A date written with one set of names converts to the other set by substitution alone, with nothing else to adjust.
Where the month sits in the year
Shahrivar, or Sunbula, is the sixth month of the Solar Hijri year and the last month of summer. The month before it is Mordad, called Asad in Afghan usage. The month after it is Mehr, called Mizan in Afghan usage, and with that month the autumn half of the year opens.
It runs 31 days, every year. This month takes no part in the leap-year adjustment, so its length never varies: the count is 31 days in an ordinary year and 31 days in a leap year alike. Its position in the sequence is equally steady — it always closes the summer, whatever Gregorian dates it happens to fall across.
Why the Gregorian dates move
The month lengths are set by the calendar's own rule, but the start of the year is not. The Solar Hijri year begins at the vernal equinox, an astronomical event that does not land on a fixed Gregorian day. Every month inherits that arrangement. So the Gregorian date on which this month begins is determined rather than chosen, and it shifts a little from year to year within a narrow window.
Across the documented range — 101 consecutive Persian years, 1329 to 1429, which for this month falls in the Gregorian years 1950 to 2050 — the month began on 22 to 24 August and ended on 21 to 23 September. That is three distinct start dates in all, unevenly distributed: one of them accounts for most of the years and the others for the remainder.
This is why a printed calendar that gives a single fixed Gregorian range for the month is right in most years and wrong in the rest. The table beneath groups the documented years by the date the month began, so the exact correspondence can be read off directly rather than assumed.
When Shahrivar began
The month lengths are set by the calendar's own rule, but the year starts at the spring equinox — so the Gregorian day this month begins on is not the same every year.
Across the 101 years below, Shahrivar began on 3 different Gregorian dates. A calendar printed with one fixed range is right for most of them and wrong for the rest.
From 1950-08-23 to 2050-09-22.
August 22
1996, 2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2029, 2032, 2033, 2036, 2037, 2040, 2041, 2044, 2045, 2048, 2049
August 23
1950, 1952, 1953, 1954, 1956, 1957, 1958, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1997, 1998, 1999, 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2010, 2011, 2013, 2014, 2015, 2017, 2018, 2019, 2021, 2022, 2023, 2025, 2026, 2027, 2030, 2031, 2034, 2035, 2038, 2039, 2042, 2043, 2046, 2047, 2050
August 24
1951, 1955, 1959
Sources
- Borkowski, The Persian Calendar for 3000 Years — the vernal-equinox anchoring that fixes every month boundary
- The Solar Hijri calendar's own month lengths: thirty-one days in the first six months, thirty in the next five, and twenty-nine or thirty in the last
- The traditional borj names, used as the month names of the Solar Hijri calendar in Afghanistan, where a month is also referred to by its number