December 21 is the first day of the winter season, which will last till the March Equinox on March 20.
Ireland's Ancient East, in conjuction with Ripplecom, will stream the solstice around the world to a potenial audience of millions. But that usually doesn't make the solstice the coldest day of the year, or put it in the middle of winter. The coldest day of the year usually lags behind a bit, because even though the amount of daylight increases as we move past the winter solstice, the Earth continues to shed more heat than it actually receives from the Sun.
Experience the wonder, as out of the morning's darkness a single ray of light illuminates the passage tomb on the shortest day of the year, marking the end of winter and the start of new life.
The solstice also marks the day with the fewest hours of sunlight in the northern hemisphere, giving the solstice the nickname the shortest day of the year. The summer solstice is when the sun's rays are directly over the Tropic of Cancer.
This year marks a very special anniversary. Of course, the winter solstice will only really affect those of us in the north. This also means equal length of day and night. The Sun then "turns around" on its journey to the summer solstice, which happens this year on June 21. The solstice, the precise time at which the axis and the sun align, marks the halfway point of this period.
The solstice always falls between the 19th and 22nd of December.
This extra quarter day is why we add a day to the calendar every four years with a leap year - to stop the dates drifting gradually through the seasons.