For observers within a couple of degrees of the equator, the period from sunrise to sunset is always several minutes longer than the night. At higher latitudes in the Northern Hemisphere, the date of equal day and night occurs before the March equinox. Daytime continues to be longer than nighttime until after the September equinox. In the Southern Hemisphere, the dates of equal day and night occur before the September equinox and after the March equinox. The chart shown below shows the dates and times for the equinoxes and solstices through 2005.
Times listed are in Mountain Standard Time.
However, you can stand an egg on end, with a large amount of patience, on any day of the year. This myth seems to pop up every year around the equinox, with the regularity of the grass greening up in the spring. The thought that an egg can only stand on end on the spring equinox due to gravitational forces of the sun being aligned with the earth sound like science, but it isn't. According to Chinese tradition, an egg can be made to stand on end at the precise moment winter ends and spring begins. But, the Chinese calender had this transition occurring at a variable time each year, determined partly by the Chinese lunar month, usually in early February.