Equinox
Around the day of the equinox, the length of the day is a little over twelve hours and the length of the night is a little under twelve hours. They are not exactly equal because the sun is not a point in the sky and because the sunlight bends as it comes to earth. The exact day and time when this happens depend on how far away from the equator it is being measured. They occur on or around March 21 and September 21. Solstices fall around June 21st and December 21st at odd intervals.