January

• first week - Hogwarts Express comes back to school from London
• winter term starts at Hogwarts

• 24 - (1995) - Second Task of the Triwizard Tournament

• 1 - (1980) - Ron Weasley's birthday

• Easter holidays - one week, Hogwarts Express transports kids back and forth
• start of summer term at Hogwarts
• (1978) - Weasley twins' birthday

• 8 - (1993) - fourth attack of the Basilisk from the Chamber of Secrets (Hermione and Penelope Clearwater)
• 26 - (1991) - Harry Potter encounters Quirrell/Voldemort in the forest
• 29 - (1993) - Harry Potter defeats Tom Riddle in the Chamber of Secrets

• first week - exams
• 4 - (1991) - Harry Potter defeats Quirrell/Voldemort in the chamber of the Sorcerer's Stone
• 24 - (1995) - Third Task of the Triwizard Tournament
• (1995) beginning of Voldemort's second rise to power
• third week - end of summer term
• Leaving Feast - awarding of points and House Cup
• Hogwarts Express travels back to London

July

• third week - Quidditch World Cup (every four years, most recently in 1994)
• 31 - Harry Potter's birthday (1980)

• last week of the month - many students can be found in Diagon Alley buying supplies for Hogwarts

• 1 - Hogwarts Express travels from King's Cross, London to Hogsmeade Station, 
• start of the school year at Hogwarts
• evening: Welcoming Feast, the Sorting
• 19 - Hermione Granger's birthday (probably 1980)
• third week - Angelina Johnson's birthday (1977)

• 31 - Halloween
• Halloween Feast at Hogwarts - 7 pm
• (1981) - near midnight - the first defeat of Voldemort by Harry Potter
• (1992) - first attack of the Basilisk from the Chamber of Secrets (Mrs. Norris)

• Hogwarts Quidditch Season begins
• 8 - (1992) - second attack by the Basilisk from the Chamber of Secrets (Colin Creevey)
• 24 - (1994) - First Task of the Triwizard Tournament

• first week - McGonagall takes names of students staying over Christmas holidays
• 17 - (1992) - first attempt at a Dueling Club at Hogwarts, led by Lockhart and Snape
• 18 - (1992) - third attack of the Basilisk from the Chamber of Secrets (Fitch-Fletchley and Nearly Headless Nick)
• third week - end of fall term, Hogwarts Express takes kids back to London