Taking from the start of the 20th century, the 21st of December was on a Friday in 1906, 1917, 1923, 1928, 1934, 1945, 1951, 1956, 1962, 1973, 1979, 1984, 1990, 2001, 2007 and 2012. It will next be on a Friday in 2018 and then 2029.
Friday 31st December 2100. The last year of the 21st century is 2100.
1966 started on a Saturday, and was not a leap year, so 21st October was a Friday.
The last time before 2014 was in 2008, the next time will be in 2025.
During the 21st century, the 16th of February is on a Friday in 2001, 2007, 2018, 2024, 2029, 2035, 2046, 2052, 2057, 2063, 2074, 2080, 2085 and 2091.
There are 183 days between the 21st of June and the 21st of December each year.
21st June is the longest day of the year and 22nd December is the shortest day of the year.
Good Friday falls on the Friday before Easter Sunday, which is determined by the first full moon after the spring equinox. The earliest date for Easter Sunday is March 22, so Good Friday will not fall on March 21st again in the foreseeable future. The last time Good Friday fell on March 21st was in 2008, and the next time it will happen is in 2103.
1925 was a common year which started on a Thursday, so 25th December was a Friday.
The northern hemisphere has more daylight hours on June 21st, which is the summer solstice and the longest day of the year. December 21st is the winter solstice and has the shortest daylight hours of the year.
If the 21st of May is a Wednesday, then Christmas Day in that year will be a Thursday.
The first day of Winter always falls on December 21st (Yule). And for the year 2011 December 21st falls on a Wednesday.
2001