18 December is the 352nd day of the year (353rd in leap years). There are 13 days remaining until the end of the year.
- 1991: The Gryffindor first year students have an Astronomy Class at midnight, on the top of the Astronomy Tower.
- 1992: A blizzard covers the school, causing the last Herbology lesson of the term to be cancelled. Justin Finch-Fletchley and Nearly Headless Nick are petrified by Slytherin's Basilisk. Fawkes the Phoenix has a Burning Day.
- 1993: A trip to Hogsmeade village takes place. Fred and George Weasley give Harry Potter the Marauder's Map, in order to allow the latter to sneak into Hogsmeade. At the Three Broomsticks, Harry overhears Cornelius Fudge, Filius Flitwick, Minerva McGonagall, Rubeus Hagrid, and Madam Rosmerta discussing Sirius Black's supposed double-cross.
- 1994: Severus Snape gives a test on antidotes to his Fourth year students. Harry Potter asks Cho Chang and Ron Weasley asks Fleur Delacour to the Yule Ball; both were unsuccessful.
- 1995: Harry Potter and Cho Chang share a kiss under the mistletoe after the last Dumbledore's Army meeting of the term. That night, Harry has a dream about Arthur Weasley being attacked by Nagini at the Department of Mysteries. Harry Potter and the Weasley children are sent to 12 Grimmauld Place by Portkey from Dumbledore's office.