Saturday

Saturday was a day of the week. The Doctor, in his fourth, tenth and eleventh incarnations, declared that he liked Saturdays. The Eleventh Doctor called it a "big temporal tipping point, when everything is possible." (PROSE: Shada, TV: The Stolen Earth, The Impossible Astronaut).

At least some schools, such as Coal Hill Secondary School, were closed on Saturdays. On every such afternoon, Susan Foreman would use the time to babysit Malcolm until the six-year-old's Aunt Junie arrived on 4 April 1963. (PROSE: Time and Relative)

Behind the scenes
Doctor Who currently,, airs regularly on Saturdays on BBC One. The series originally premiered on Saturday as well, and regularly aired on that day of the week.