Julian calendar

The Julian calendar reform lengthened seven months and replaced the intercalary month with an intercalary day to be added every four years to February. It was based on a length for the year of 365 days and 6 hours (365.25 d), while the mean tropical year is about 11 minutes and 15 seconds less than that. This had the effect of adding about three quarters of an hour every four years. The effect accumulated from inception in 45 BC until the 16th century, when the northern vernal equinox fell on 10 or 11 March.^[16]

The date in 1452 was 11 March, 11:52 (Julian).^[17] In 2547 it will be 20 March, 21:18 (Gregorian) and 3 March, 21:18 (Julian).^[18]

Abrahamic tradition

• The Jewish Passover usually falls on the first full moon after the Northern Hemisphere vernal equinox,^[19] although occasionally (currently three times every 19 years^{[citation needed]}) it will occur on the second full moon.^[20]
• The Christian Churches calculate Easter as the first Sunday after the first full moon on or after the March equinox. The official church definition for the equinox is 21 March. The Eastern Orthodox Churches use the older Julian calendar, while the western churches use the Gregorian calendar, and the western full moons currently fall four, five or 34 days before the eastern ones. The result is that the two Easters generally fall on different days but they sometimes coincide. The earliest possible western Easter date in any year is 22 March on each calendar. The latest possible western Easter date in any year is 25 April.^[21]

Iranian tradition

• The northward equinox marks the first day of various calendars including the Iranian calendar. The ancient Iranian peoples' new year's festival of Nowruz can be celebrated 20 March or 21 March. According to the ancient Persian mythology Jamshid, the mythological king of Persia, ascended to the throne on this day and each year this is commemorated with festivities for two weeks. Along with Iranian peoples, it is also a holiday celebrated by Turkic people, the North Caucasus and in Albania. It is also a holiday for Zoroastrians, adherents of the Baháʼí Faith and Nizari Ismaili Muslims irrespective of ethnicity.^[22]

West Asia and North Africa

• In many Arab countries, Mother's Day is celebrated on the northward equinox.^{[citation needed]}
• Sham el-Nessim is a modern celebration which is claimed by some to have been celebrated in ancient Egypt but with little evidence. It is one of the public holidays in Egypt. It is assumed by some that sometime during Egypt's Christian period (c. 200–639) the date moved to Easter Monday, but before then it coincided with the vernal equinox.^{[citation needed]}

South and Southeast Asia

According to the sidereal solar calendar, celebrations which originally coincided with the March equinox now take place throughout South Asia and parts of Southeast Asia on the day when the Sun enters the sidereal Aries, generally around 14 April.

• In Cambodia, the Angkor Wat Equinox is a solar phenomenon which dates back to the reign of Suryavarman II.

East Asia

• The traditional East Asian calendars divide a year into 24 solar terms (节气, literally "climatic segments"), and the vernal equinox (Chūnfēn, Chinese and Japanese: 春分; Korean: 춘분; Vietnamese: Xuân phân) marks the middle of the spring. In this context, the Chinese character 分 means "(equal) division" (within a season).
• In Japan, Vernal Equinox Day (春分の日 Shunbun no hi) is an official national holiday, and is spent visiting family graves and holding family reunions.^[23][24] Higan (お彼岸) is a Buddhist holiday exclusively celebrated by Japanese sects during both the Spring and Autumnal Equinox.^[23]

Europe

• Hilaria was an ancient Roman festival commemorating the death and resurrection of Attis.
• Lieldienas
• in Norse paganism, a Dísablót was celebrated on the vernal equinox.^[25]
• Drowning of Marzanna

The Americas

• Spring equinox in Teotihuacán
• The reconstructed Cahokia Woodhenge, a large timber circle located at the Mississippian culture Cahokia archaeological site near Collinsville, Illinois,^[26] is the site of annual equinox and solstice sunrise observances. Out of respect for Native American beliefs these events do not feature ceremonies or rituals of any kind.^[27][28][29]

Modern culture

• World Storytelling Day is a global celebration of the art of oral storytelling, celebrated every year on the day of the northward equinox.^{[citation needed]}
• World Citizen Day occurs on the northward equinox.^[30]
• The Baháʼí calendar year starts at the sunset preceding the March equinox calculated for Tehran.^[31]
• In Annapolis, Maryland, United States, boatyard employees and sailboat owners celebrate the spring equinox with the "Burning of the Socks" festival. Traditionally, the boating community wears socks only during the winter. These are burned at the approach of warmer weather, which brings more customers and work to the area. Officially, nobody then wears socks until the next equinox.^[32][33]
• Neopagans observe the March equinox (referred to as Ostara) as a cardinal point on the Wheel of the Year. In the northern hemisphere some varieties of paganism adapt vernal equinox celebrations, while in the southern hemisphere pagans adapt autumnal traditions.^{[citation needed]}
• International Astrology Day^{[citation needed]}
• On 20 March 2014 and 20 March 2018, the March equinox was commemorated by an animated Google Doodle.^[34]