A half-birthday is a day approximately six months before or after the anniversary of a person's birth. It is sometimes marked by people whose birthday either falls on major holidays, near major holidays, or both, the celebration of which may overshadow celebration of the birthday. [1] It may also be marked by students whose birthday does not occur during the regular school year; a half-birthday allows a celebration with friends at school, with half a cake. [2]
There are two ways to calculate half-birthdays.
The easier but less precise method is to take the number of the date of the birthday and advance the month by six: e.g. April 20 becomes October 20. More than 75% of the time this method results in a wrong date. [3] Months don't all have the same number of days, leap years add a day, and the second half of the year is longer than the first half. A good example where this doesn't work is six months after an August 30 birthday would be February 30, which is nonexistent in the Gregorian calendar.
Accurate calculations require the addition or subtraction of half the number of days in a year from the birth date taking into account if the time period includes a leap day or not. In the case of a common year, this would be 182.5 days. In leap years, the number of days would be 183. This method would lead to a March 1 or February 29 half-birthday for an August 31 birthday, depending on whether it's a leap year. [4]
In the U.S., some tax-related penalties are related to half-years, such as a 10% penalty for making an early withdrawal from an IRA before age 59½. The federal government defines the half-year as being "six calendar months" after the anniversary of birth, regardless of what day of the month this produces. [5]
In many states in the U.S., the minimum age to obtain a learner permit occurs on a half-birthday, such as 14½ in Idaho, 14 years and eight months in Michigan, 15½ in California, and 15 years and nine months in Maryland. The same is true for receiving a restricted license for a minor in many states.
At least three children's books have been written about half-birthdays:
Mentions in TV Series
February is the second month of the year in the Julian and Gregorian calendars. The month has 28 days in common years or 29 in leap years, with the 29th day being called the leap day. It is the first of five months not to have 31 days and the only one to have fewer than 30 days. February is the third and last month of meteorological winter in the Northern Hemisphere. In the Southern Hemisphere, February is the third and last month of meteorological summer.
The French Republican calendar, also commonly called the French Revolutionary calendar, was a calendar created and implemented during the French Revolution, and used by the French government for about 12 years from late 1793 to 1805, and for 18 days by the Paris Commune in 1871, and meant to replace the Gregorian calendar.
The Hebrew calendar, also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance and as an official calendar of Israel. It determines the dates of Jewish holidays and other rituals, such as yahrzeits and the schedule of public Torah readings. In Israel, it is used for religious purposes, provides a time frame for agriculture, and is an official calendar for civil holidays alongside the Gregorian calendar.
The Julian calendar is a solar calendar of 365 days in every year with an additional leap day every fourth year. The Julian calendar is still used as a religious calendar in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Amazigh people.
A leap year is a calendar year that contains an additional day compared to a common year. The 366th day is added to keep the calendar year synchronised with the astronomical year or seasonal year. Since astronomical events and seasons do not repeat in a whole number of days, calendars having a constant number of days each year will unavoidably drift over time with respect to the event that the year is supposed to track, such as seasons. By inserting ("intercalating") an additional day—a leap day—or month—a leap month—into some years, the drift between a civilization's dating system and the physical properties of the Solar System can be corrected.
The International Fixed Calendar is a proposed calendar reform designed by Moses B. Cotsworth, first presented in 1902. The International Fixed Calendar divides the year into 13 months of 28 days each. A type of perennial calendar, every date is fixed to the same weekday every year. Though it was never officially adopted at the country level, the entrepreneur George Eastman instituted its use at the Eastman Kodak Company in 1928, where it was used until 1989. While it is sometimes described as the 13-month calendar or the equal-month calendar, various alternative calendar designs share these features.
Vesak, also known as Buddha Jayanti, Buddha Purnima, and Buddha Day, is a holiday traditionally observed by Buddhists in South Asia and Southeast Asia, as well as Tibet and Mongolia. It is among the most important Buddhist festivals. The festival commemorates the birth, enlightenment (Nibbāna), and death (Parinirvāna) of Gautama Buddha in Theravada, Tibetan Buddhism and Navayana.
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Japanese calendar types have included a range of official and unofficial systems. At present, Japan uses the Gregorian calendar together with year designations stating the year of the reign of the current Emperor. The written form starts with the year, then the month and finally the day, coinciding with the ISO 8601 standard.
Adherents of Zoroastrianism use three distinct versions of traditional calendars for liturgical purposes, all derived from medieval Iranian calendars and ultimately based on the Babylonian calendar as used in the Achaemenid empire. Qadimi ("ancient") is a traditional reckoning introduced in 1006. Shahanshahi ("imperial") is a calendar reconstructed from the 10th century text Denkard.
As a moveable feast, the date of Easter is determined in each year through a calculation known as computus. Easter is celebrated on the first Sunday after the Paschal full moon. Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the Julian or Gregorian calendar. The complexity of the algorithm arises because of the desire to associate the date of Easter with the date of the Jewish feast of Passover which, Christians believe, is when Jesus was crucified.
The Attic calendar or Athenian calendar is the lunisolar calendar beginning in midsummer with the lunar month of Hekatombaion, in use in ancient Attica, the ancestral territory of the Athenian polis. It is sometimes called the Greek calendar because of Athens's cultural importance, but it is only one of many ancient Greek calendars.
An anniversary is the date on which an event took place or an institution was founded in a previous year, and may also refer to the commemoration or celebration of that event. The word was first used for Catholic feasts to commemorate saints.
The Ethiopian calendar, or Ge'ez calendar is the official state civil calendar of Ethiopia and serves as an unofficial customary cultural calendar in Eritrea, and among Ethiopians and Eritreans in the diaspora. It is also an ecclesiastical calendar for Ethiopian Christians and Eritrean Christians belonging to the Orthodox Tewahedo Churches, Eastern Catholic Churches, and Eastern Protestant Christian P'ent'ay Churches. The Ethiopian calendar is a solar calendar that has much in common with the Coptic calendar of the Coptic Orthodox Church of Alexandria and Coptic Catholic Church, but like the Julian calendar, it adds a leap day every four years without exception, and begins the year on 11 or 12th of September in the Gregorian calendar. A gap of seven to eight years between the Ethiopian and Gregorian calendars results from an alternative calculation in determining the date of the Annunciation.
The Symmetry454 calendar (Sym454) is a proposal for calendar reform created by Irv Bromberg of the University of Toronto, Canada. It is a perennial solar calendar that conserves the traditional month pattern and 7-day week, has symmetrical equal quarters in 82% of the years in its 293-year cycle, and starts every month on Monday.
Buddha's Birthday or Buddha Day is a primarily Buddhist festival that is celebrated in most of South, Southeast and East Asia, commemorating the birth of the prince Siddhartha Gautama, who became the Gautama Buddha and founded Buddhism. According to Buddhist tradition and archaeologists, Gautama Buddha, c. 563-483 BCE, was born at Lumbini in Nepal. Buddha's mother was Queen Maya Devi, who delivered the Buddha while undertaking a journey to her native home, and his father was King Śuddhodana. The Mayadevi Temple, its gardens, and an Ashoka Pillar dating from 249 BCE mark the Buddha's birth place at Lumbini.
The Pax calendar was invented by James A. Colligan, SJ in 1930, as a perennializing reform of the annualized Gregorian calendar.
A birthday is the anniversary of the birth of a person, or figuratively of an institution. Birthdays of people are celebrated in numerous cultures, often with birthday gifts, birthday cards, a birthday party, or a rite of passage.
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A perennial calendar is a calendar that applies to any year, keeping the same dates, weekdays and other features.