June/July 1996:
* Start of summer: Harry discovers the Half-Blood Prince's potions book and begins practicing its advanced potions.
* July 1st: Harry and Ron witness the return of Voldemort through a vision.
* Mid-July: Harry learns of Dumbledore's plan to find Voldemort's horcruxes.
* End of July: Dumbledore and Harry visit Slughorn to seek information about Voldemort's past.
September 1996:
* Start of term: Harry starts his sixth year at Hogwarts.
* First few weeks: Harry begins his relationship with Ginny Weasley.
* First Quidditch Match: Harry plays for Gryffindor against Slytherin.
* October: Dumbledore's Army is reformed and Harry, Ron, and Hermione start teaching other students defensive magic.
* November: Harry and Dumbledore go on several secret missions to find horcruxes.
* December: Harry attends Slughorn's Christmas party and witnesses a tense confrontation between Dumbledore and Snape.
January 1997:
* Early January: Harry and Dumbledore visit the cave where Voldemort hid his first horcrux.
* Mid-January: Harry confronts Snape, who reveals information about his past and his connection to Voldemort.
* End of January: Dumbledore is fatally injured by Severus Snape.
February 1997:
* Early February: Dumbledore's funeral is held.
* Mid-February: Harry and the other DA members plan their resistance against Voldemort's regime.
* End of February: Harry is informed that Voldemort's army is gathering.
March 1997:
* Start of March: Harry receives the locket horcrux from Ron and Hermione.
* Mid-March: Harry, Ron, and Hermione go on a quest to find the other horcruxes.
April 1997:
* Start of April: Harry, Ron, and Hermione are forced to abandon their mission after a confrontation with Voldemort.
* Mid-April: Harry and Dumbledore's memories are revealed to the entire school.
* End of April: Harry learns about the prophecy regarding him and Voldemort.
May 1997:
* Start of May: Harry and his friends prepare for the final battle against Voldemort.
* Mid-May: Harry and Ron discover the whereabouts of the locket horcrux.
* End of May: Harry, Ron, and Hermione destroy the locket horcrux.
June 1997:
* Start of June: Harry and his friends return to Hogwarts.
* Mid-June: The Battle of Hogwarts begins.
* End of June: Voldemort is defeated and Harry, Ron, and Hermione emerge victorious.
Note: The exact timeline may vary slightly depending on interpretation and various sources.