Spring equinox. Computer artwork showing the apparent path of the sun in the sky as seen from the Earth on the spring equinox. An equinox occurs twice a year (around 20th March and 22nd September), when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the centre of the Sun being in the same plane as the Earth's equator. At an equinox the Sun is at one of two opposite points on the celestial sphere where the celestial equator and ecliptic intersect. These points of intersection are called equinoctial points.