The spring equinox, or a date close to it, anchors seasonal observances across a wide range of cultures independent of any shared origin, reflecting the equinox's status as an astronomically obvious marker available to any society tracking the sun's path. Nowruz, the Persian New Year, falls on the March equinox itself and is observed across Iran, Central Asia, and the wider Persianate world by communities of several different religious backgrounds, rooted in pre-Islamic Zoroastrian tradition and centered on renewal, the cleaning and refreshing of homes, and family gatherings marking the literal astronomical new year.
Christian Easter, while not fixed to the equinox directly, is calculated in relation to it, following the ancient rule that sets Easter on the first Sunday after the first full moon occurring on or after the spring equinox, a computational method called computus that has itself been the subject of considerable historical debate and differing calculation traditions between Eastern and Western Christianity.
Modern Wiccan and broader neopagan practice observes the spring equinox as Ostara, one of the eight sabbats of the Wheel of the Year, associated with themes of balance, fertility, and renewed growth that draw loosely on older European folk custom and on the reconstructed, rather than continuously transmitted, framework modern Pagan traditions have built around the solar year's turning points.
Sources Nowruz, UNESCO Representative List of the Intangible Cultural Heritage of HumanityUNESCO Intergovernmental Committee for the Safeguarding of the Intangible Cultural Heritage with The Triumph of the Moon: A History of Modern Pagan WitchcraftRonald Hutton