The spring equinox, falling on or near the twentieth of March, is the hinge of the month's religious life. Nowruz begins the Persian year at the equinox with the setting of the haft sin table, the jumping of bonfires and the visiting of family, a festival older than Islam that Zoroastrians keep as sacred and that is now celebrated by some three hundred million people from the Balkans to Central Asia. Modern Pagans keep the same moment as Ostara, one of the eight stations of the Wheel of the Year, taking the name from Eostre, the Anglo Saxon goddess whom Bede records as giving her name to the Easter season. Japanese Buddhists keep Higan in the equinox week, visiting family graves as day and night come into balance.
Fixed dates carry the rest of the month. Hinamatsuri, the doll festival of the third of March, sets out tiered displays of imperial court dolls for the health of daughters, with roots in Shinto purification rites that floated paper dolls downriver bearing misfortune away. The Annunciation on the twenty fifth of March marks Gabriel's announcement to Mary nine months before Christmas, a feast kept in East and West alike, and its old role as the start of the English legal year is the reason the modern British tax year still opens in early April, the same date shifted by the calendar reform of 1752.
Movable feasts crowd March as well: Ash Wednesday and much of Lent usually fall in it, Holi splashes northern India with colour at the full moon of Phalguna, and Purim, celebrating the deliverance told in the Book of Esther, most often lands in the month.
Sources Zoroastrians: Their Religious Beliefs and PracticesMary Boyce with Pagan Goddesses in the Early Germanic World: Eostre, Hreda and the Cult of MatronsPhilip A. Shaw, The Oxford Dictionary of the Christian Church, 3rd revised editionF. L. Cross and E. A. Livingstone (eds.)