22 December

22 December was the date of San Claar Divination Day in the Predestined systems, a winter celebration. (PROSE: Time Traveller's Diary)

In 1963, the Fifth Doctor and Nyssa visited Switzerland, where they solved the mystery of a school haunting and prevented the Spillager invasion of Earth. (AUDIO: Winter for the Adept)

In 1984, Ruby Sara Duvall was born. (PROSE: Iceberg)

According to a calendar on the Snowcap base, 22 December 1986 was a Monday. (TV: The Tenth Planet)

In 2005, while in her aunt's house in Devon, Sally Sparrow tore off a piece of wallpaper, revealing a message from 1985 asking for help. After later finding a photograph with the Ninth Doctor asking to look through the wallpaper again, she found another message leading her to play a video recording of the Doctor in 1985; the Doctor communicating to Sally through already having the conversation from Sally's uncompleted Christmas homework.

The Doctor explained that the TARDIS had "burped" forward in time twenty years to this year and needed Sally's help. Sally's future self appeared, telling Sally to hit the TARDIS reset button to reach the Doctor. The Doctor told Sally to finish her homework detailing this conversation and the messages left to her first, which she did. Sally then piloted the TARDIS to the Doctor to rescue him. (PROSE: What I Did on My Christmas Holidays by Sally Sparrow)

In 2006, the SS Elysium found itself deep underneath the continent of Antarctica, its passengers facing Cyber-conversion. Journalist Ruby Duvall left a message on "Nano" lest someone discover it; it was her 22nd birthday. She and the Seventh Doctor survived; afterwards, Ruby was offered a chance to travel in the Doctor's TARDIS. However, she missed the flight by seconds when she went to retrieve her camera. (PROSE: Iceberg)