December 25 is celebrated worldwide as Christmas.
- Timeline 1
- 0000: On Saturday, October 26, Doc Brown demonstrated the time circuits by setting the time to this date in the year 0000, if one wanted to witness the birth of Jesus Christ. However, there is no year "0" between 1 B.C. and 1 A.D., nor is there proof that Jesus was born on December 25, although the anniversary of his birth is celebrated annually on that day.
- Timeline 2
- 1964 - 1969: After an elderly Biff Tannen made himself rich by traveling back to 1955 to give his younger self a Grays Sports Almanac, his younger self became a millionaire by gambling as he knew the results before they happened. He used his wealth to send Lorraine Baines McFly a box of toys for her children, Dave, Linda, and Marty, every Christmas.
- 1970, Friday: After the seventh year straight of receiving presents from Biff, George McFly states that it needs to stop. Lorraine wants to leave Hill Valley, but George convinces her to let the family stay as he doesn't want to take the children away from their grandparents.
- Timeline 3
- 1845, Thursday: In London, England, Ebiffnezer Tannen wakes up after being visited in the night by Marty McFly who, using A Christmas Carol as inspiration, posed as the Ghost of Christmas while flying on a hoverboard. Tannen has a change of heart after this encounter, and releases everyone from the debtor's prison.
Behind the scenes
- Bob Gale has stated in the DVD commentary that it was an example of a joke that nobody else laughed at -- the idea that a scientist that specialized in time travel experiments for the past 30 years would punch in a nonexistent year "DEC 25 0000" to witness the birth of Christ.