What is the Spring Equinox

         

The Spring Equinox, more commonly known as Vernal Equinox, is at the start of spring and the days and nights are each approximately 12 hours long.  Every year the earth goes once around the Sun; that is, after all, the definition of a year. The earth spins on its axis, and the axis happens to be tilted about 23.5 degrees relative to earth's orbital plane. As a result, sometimes the northern hemisphere is tilted toward the sun and sometimes the southern hemisphere tilts toward the sun. The change isn't severe, but it is enough to cause the seasons. When the north is tilting toward the sun we generally experience warmer weather in the north. When the south is tilted toward the sun then the southern hemisphere generally experiences the warmer weather.  According to the Almanac, the first day of Spring is March 20th, but I hold true to the belief that all the solstices and equinoxes land on the 21st.  The term equinox can also be used in the broader sense, meaning the date when such a passage happens.