1 September is the 244th day of the year (245th in leap years). There are 121 days remaining until the end of the year.
- The Hogwarts Express leaves London at precisely eleven o'clock in the morning, and arrives at Hogsmeade Station sometime after nightfall. The Sorting ceremony takes place in the Great Hall and the Hogwarts school year starts.
- 1892: Albus Dumbledore and Elphias Doge meet on their first day at Hogwarts. Dumbledore was believed to be, by the rest of the students, a Muggle-hater, as his father had been arrested for attacking three young Muggles; Doge had a pock-marked face and a greenish hue that was left from contracting dragon pox shortly before arriving at school — they became friends as both felt like outsiders.
- 1938: Tom Riddle begins at Hogwarts and is Sorted into Slytherin.
- 1991: Harry Potter, Hermione Granger, and Ron Weasley are Sorted into Gryffindor.
- 1991: Dudley Dursley is in London having his tail removed that was created by magic.
- 1992: Harry Potter and Ron Weasley miss the Hogwarts Express (due to Dobby) and travel to the school with the Flying Ford Anglia. They crash onto the Whomping Willow by accident. The car drives off, presumably into the Forbidden Forest, and Ron's wand comes close to breaking.
- 1993: Dementors board the Hogwarts Express during the trip to Hogwarts; Remus Lupin drives them away from Harry Potter, who fainted due to the power of the Dementors.
- 1994: During the early morning, Amos Diggory calls on Arthur Weasley to help Alastor Moody after a disturbance at his house. Bartemius Crouch Jr. (impersonating Moody), who has abducted Moody, claims he has been attacked by burglars.
- 1995: Harry Potter meets Luna Lovegood in the Hogwarts Express.
- 1996: The first meeting of the Slug Club takes place on the Hogwarts Express, with students such as Harry Potter, Ginny Weasley and Neville Longbottom attending. Harry sneaks into Draco Malfoy's compartment and gets a Full Body-Bind curse put on him by the latter. Nymphadora Tonks rescues him and Severus Snape takes him in to the Welcoming Feast.
- 1997: More Death Eaters appear outside 12 Grimmauld Place. The Daily Prophet announces that Severus Snape is made Headmaster of Hogwarts School. Harry, Ron, and Hermione decide to infiltrate the Ministry of Magic the next day. Neville Longbottom, Ginny Weasley and Luna Lovegood return to Hogwarts.
- 2009: Teddy Lupin begins at Hogwarts.
- 2011 or 2012: Victoire Weasley begins at Hogwarts.
- 2015: James Potter II begins at Hogwarts.
- 2017: Albus Potter, Rose Weasley, and Scorpius Malfoy begin at Hogwarts.