The equinox, the seasons, and the changing length of daylight hours throughout the year are all due to one fact: The Earth spins on a tilted axis.
The vernal (tr. spring) equinox (tr. equal night) is upon us today, Tuesday, March 20th. Both the Northern and Southern Hemispheres will be experiencing an equal amount of daylight hours. For those of us here in the Northern Hemisphere, it marks the beginning of SPRING, with daylight hours continuing to lengthen until the summer solstice in June.
The green arrow on the rock shows an imaginary revolution of a rock representing for the purpose of illustration - the earth on its axis) It has equal shaded green to non-shaded green. This shows on one spin of the earth there is equal length of darkness to daylight at the equinox.
The green arrow in the photo below showing the orientation representing autumn and winter months prior to the equinox, when the earth axis is turned away from the sun, has more of its circular length in darkness, and so we in the northern hemisphere, up to now, have had days with less daylight (and thus nights are not equal to daylight time. We've missed our time in the sun.
But now it's time to have fun in the sun,
Spring is nature's way of saying. "Let's Party"
(sorry, for all of you down under)