Solstice And Equinox Dates 2025. The data is provided by the institut de mécanique céleste et de calcul des éphémérides. The vernal equinox marks the.
An equinox is one of two days in the year when the sun crosses the equator and day and night become equal in length. Spring begins with the vernal equinox, thursday, march 20, 2025, 5:01 a.m.