In the northern hemisphere it is the shortest day in terms of daylight and it is in winter, but it is normally not the coldest day. The colder days tend to be after that. In the southern hemisphere it would normally be a warm day.
The coldest day ever in Seattle was December 31, 1950. It was 0 °F!
The coldest day on record in Redding, California was on December 8, 1972 when the temperature dropped to 17°F.
December 21 2012 will be a Friday.
December 21 1978 was a Thursday.
21 December 2012 will be a Friday.
December 21, 2055 will be a Tuesday.
December 21 1951 was a Friday.
December 21 1950 was on a Thursday.
21 December 1995 was a Thursday.
December 21, 1952 fell on a Sunday.
December 21, 1962 was a Friday.
December 21 2012 will be a Friday.