My friends who celebrate the Solstice were confused about the date this year. Isn’t Solstice always on December 21? Well, no: The actual date can vary from Dec 20 to Dec 23, depending upon the Gregorian calendar.
Furthermore, Solstice technically is a moment in time, not an entire day. The moment of Solstice occurs when the Sun enters 0 degrees 0 minutes of Capricorn. Put in scientific terms, Solstice is when the Earth reaches its maximum axial tilt away from the Sun.
For those of us in the Midwest USA, the moment of Solstice was Wednesday, December 21 at 11:30 p.m. Central Standard Time (CST). The official Solstice date, however, was December 22. Why? Because the convention is to use Universal Time (UT) for such events. UT is measured at the Prime Meridian, or 0 Longitude on planet Earth. At 11:30 p.m. last Wednesday in Milwaukee it was 5:30 a.m. in Greenwich, England, the current site of the Prime Meridian. (The Prime Meridian used to run through Paris, but that is another story!) Solstice Day--the day that contains the Solstice moment, UT—is the first day of winter. In old times this day was called Midwinter, in the same way that Summer Solstice was known as Midsummer.
“A Midsummer Night’s Dream,” then, takes place on the Summer Solstice. Summer Solstice is to the solar year as the full moon is to the lunar month. That’s why the play is full of such antics—it is like full-moon time, but much stronger! Winter Solstice is the rebirth of the Sun, just as the Moon is ‘reborn’ at each new moon.
For some interesting info on the Gregorian calendar and how/why it came about, check this URL: http://en.wikipedia.org/wiki/Gregorian_calendar