Autumn Equinox 2024 Uk. The astronomical calendar determines the seasons due to the 23.5 degrees of tilt of the earth's rotational axis in. The equinox in the northern hemisphere occurs twice a year around 20 march (the spring equinox) and around 22 september (the autumn.
But did you know there are actually three main definitions for the season coming. The equinox is the time or date (twice each year) at which the sun crosses the celestial equator and when day and night are of equal length.