Noun
March 21
Source: WordNetAlthough the instant of the full moon must occur after the instant of the vernal equinox, it may occur on the same day. Source: Internet
However, due to intercalary months or leap months falling after the vernal equinox, Passover sometimes starts on the second full moon after vernal equinox, as in 2016. Source: Internet
In 1904 the vernal equinox was on a 21st, and it was the day after Aleister Crowley ended his Horus Invocation that brought on the new Æon and Thelemic New Year. Source: Internet
Celestial coordinate systems The vernal equinox occurs in March, about when the Sun crosses the celestial equator south to north. Source: Internet
In the southern hemisphere, the vernal equinox occurs in September and the autumnal equinox in March. Source: Internet
Its traditional name is derived from "sharatayn", the Arabic word for "the two signs", referring to both Beta and Gamma Arietis in their position as heralds of the vernal equinox. Source: Internet