Where I live, about 4:23 or 4:31 (PDT) on September 23, 1999 is the time of the fall or autumnal equinox. (That is 11:23 or 11:31 Universal Time, from two different sources.) When celebrating that moment, in the southern hemisphere of earth, it might be a different day, but it is called the spring or vernal equinox. Anywhere though, night and day are equal in length. And it really happens at exactly the same moment or instant all over earth.
The United Nations sponsors a World Peace day global event at noon where you are on September 21. That is 12 o'clock midday on the third Tuesday in September. Take a minute to stand in silent solidarity to support the United Nations General Assembly delegates as they begin the year's work. See World Peace day.
For more events, see Global Meditations and Wrinkle links (this is Wrinkle 8, coming up). Stargates of Earth Link Mission. The first of the Gates opens on September 19, so the 12 days before the Gate begin on September 12th, a few days from now. The last Gate on September 21, and add 12 days for the energies to integrate and wind down, is October 3rd!