The 1990s
1991 (Y11) AD = 110 MM = 66 TR = 65 RH = 63 M = 33 BW = 21 CW = 19 PW = 15 FGW = 13 HG = 12 H&R = 11 GW = 10
The [Nimbus 2000] [broomstick] is releasedA display model appears in the window of [Quality Quidditch Supplies].
(PS5)
[Slytherin] wins both the [Quidditch Cup] and the [House Cup] ([PS7], [PS13])They "flatten" [Gryffindor] in the final [Quidditch] match, according to [McGonagall] ([PS9]).
[Dudley]'s eleventh birthday[Harry] accompanies [Dudley], [Piers Polkiss], [Aunt Petunia], and [Uncle Vernon] to the [zoo], where he first exercises his gift of being a [Parselmouth] to speak with a [boa constrictor].
This is a Saturday according to the book. It comes approximately one month before [Harry]'s birthday. That morning, Dudley receives a video camera for his birthday:
"At that moment the telephone rang and [Aunt Petunia] went to answer it while [Harry] and [Uncle Vernon] watched [Dudley] unwrap the racing bike, a video camera..." ([PS2])
After the [zoo] incident on Dudley's birthday, [Harry] is confined to his cupboard for a few weeks. By the end of that period, the video camera is broken:
"By the time he was allowed out of his cupboard again, the summer holidays had started and Dudley had already broken his new video camera..." ([PS3])
Then, a week before [Harry]'s birthday, on the 24th of July, [Harry] receives a letter addressed to him in his cupboard under the stairs. [Uncle Vernon] moves [Harry] to [Dudley]'s second bedroom upstairs, where [Harry] sees the video camera and we learn that [Dudley]'s birthday was a month ago:
"Nearly everything in here was broken. The month-old video camera was lying on top of a small, working tank..." ([PS3])
We know from the book that July the 24th was a Tuesday. The Saturday approximately one month before Tuesday, July 24, would be Saturday, June 23. So we know that [Dudley]'s birthday is June 23. Like most dates in the books, this doesn't correspond to the dates in any particular "real life" calendar.
(PS2)
Letters begin arriving, via [owl] post, to invite [Harry Potter] to [Hogwarts]The dates are determined by counting back from the established date of July 31 for [Harry]'s birthday.
We are told the days on which these dates fall:
Monday. This reminded [Harry] of something. If it was Monday -- and you could usually count on [Dudley] to know the days the week, because of television -- then tomorrow, Tuesday, was [Harry]'s eleventh birthday.
In the "real" 1991, however, July 31 fell on a Wednesday.
(PS3)
[Harry]'s 11th birthdayHow do we know that [Harry] was born on July 31? This has been established in many places in the books, perhaps most importantly in [Dumbledore]'s discussion of the [prophecy] in [OP37]. However, we can first determine this from [PS8]. In the Daily Prophet, [Harry] reads:
"GRINGOTTS BREAK-IN LATEST -- Investigations continue into the break-in at [Gringotts] on 31 July..."
He reacts in surprise:
"[Hagrid]!" said [Harry], "that Gringotts break-in happened on my birthday! It might've been happening while we were there!"
(PS8)
Just after midnight, [Hagrid] arrives at the [hut-on-the-rock]He brings [Harry] a birthday cake and invites him to [Hogwarts].
(PS4)

[Hagrid] and [Harry] visit [Diagon Alley]While there:
[Hagrid] retrieves the [Philosopher's Stone] from the [Gringotts]' high security vaults.
[Harry] meets [Draco Malfoy] for the first time in [Madam Malkin's Robes for All Occasions].
[Hagrid] buys [Hedwig] as a birthday present for [Harry].
original artwork © 2001 [Laura Freeman], used by permission
(PS5)
[Percy Weasley] gives his pet rat, [Scabbers], to his younger brother [Ron]Like nearly everything [Ron] owns, [Scabbers] is secondhand and a bit battered ([PA4]).
Scabbers is later revealed to be [Peter Pettigrew] in disguise ([PA17]).
"His name's Scabbers and he's useless, he hardly ever wakes up. [Percy] got an [owl] from my dad for being made a prefect, but they couldn't aff -- I mean, I got Scabbers instead" ([PS6]).
From the comments made by [Ron] on the [Hogwarts Express] that September, it would seem that [Ron] received Scabbers from [Percy] when [Percy] was given his owl upon being made [Prefect]. Assuming that [Ron] and his brothers received their [Hogwarts] letters at the same time that [Harry] would have received his, had [Uncle Vernon] not intervened, then we know that [Percy] was made [Prefect] on July 24. Sometime after that, [Molly] and [Arthur] bought [Percy] his new owl, [Hermes]. This may very well have been when the [Weasleys] came to [Diagon Alley] to buy their school things.
[Voldemort], disappointed by [Quirrell]'s inability to steal the [Philosopher's Stone], decides to inhabit him[Quirrell] begins wearing a turban to hide [Voldemort]'s face, which is sticking out of the back of [Quirrell]'s head.
(PS17)
[Uncle Vernon] and [Aunt Petunia] treat [Harry] as if he doesn't exist"[Harry]'s last month with the Dursleys wasn't fun. True, Dudley was now so scared of [Harry] he wouldn't stay in the same room, while Aunt Petunia and Uncle Vernon didn't shut [Harry] in his cupboard, force him to do anything, or shout at him -- in fact, they didn't speak to him at all. Half terrified, half furious, they acted as though any chair with [Harry] in it were empty."
(PS6)

[Harry Potter], [Hermione Granger], [Ron Weasley], [Neville Longbottom], [Draco Malfoy], and their classmates travel by way of the [Hogwarts Express] to [Hogwarts].
(PS6)
[Dudley Dursley] undergoes surgery for the removal of a pig's tail from his rather large behind"Why are you going to [London]?" [Harry] asked, trying to keep things friendly.
"Taking [Dudley] to the hospital," growled [Uncle Vernon]. "Got to have that ruddy tail removed before he goes to [Smeltings]."
(PS5)
Harry begins his classes at Hogwarts
Harry's first potions class
Harry discovers that Professor Snape actively dislikes him when he embarrasses Harry in front of the rest of the class.
Harry and Ron visit Hagrid
Harry takes Ron to visit Hagrid in his hut near the forbidden forest. While Fang slobbers all over Ron, Harry tells Hagrid about his classes and that he thinks Snape hates him. Harry reads a Daily Prophet article about the break-in at Gringotts which had happened on July 31.
[Gryffindors] and [Slytherins] have their first flying lesson[Harry] is subsequently made [Seeker] on the [Gryffindor Quidditch team] by [Professor McGonagall].
This happens on the second Thursday of the school term.
"...they spotted a notice pinned up in the [Gryffindor] common room that made them all groan. Flying lessons would be starting on Thursday..."
The date can be determined from the fact that this is the Thursday of the second week of school, it must logically be the 12th, since classes started on the 2nd.
How do we know that this is the Thursday of the second week? Because when [Harry] is following [McGonagall] away from his flying lesson, he is afraid that he will be expelled. He thinks to himself:
"Now he'd done it. He hadn't even lasted two weeks."
However, when [Fred and George] hear about this, they say:
"I tell you, we're going to win that [Quidditch Cup] for sure this year...We haven't won since [Charlie] left, but this year's team is going to be brilliant."
According to Rowling's statement that [Charlie] is three years older than [Percy], [Charlie] just left two months before. There's been no time for them not to have won "since [Charlie] left." They haven't PLAYED since [Charlie] left. Again, this is an error in the text.
(PS9)
The Halloween FeastThe feast is interrupted by a [Mountain Troll] who almost kills [Hermione Granger]; she is saved by [Harry] and [Ron], after which they become friends.
Meanwhile, [Quirrell], who let the [troll] in, heads for the [Philosopher's Stone] - but is stopped by [Snape].
We have already seen that we can't trust the "real" calendar to give us the days of the week when we know the date, but just for interest sake, Halloween in 1991 was on a Thursday. The [Gryffindor] first years had [Charms] that morning and learned the [Wingardium Leviosa] spell.
(PS10)
[Harry]'s first [Quidditch] match[Quirrell] tries to knock [Harry] off his broom during the match but is thwarted by [Severus Snape] - not to mention some pretty cool acrobatics by Harry. The match ends soon afterward when [Harry] catches the [Snitch] in his mouth for a [Gryffindor] victory.
(PS11)
[Harry] receives [James Potter]'s [Invisibility Cloak] as a Christmas present from [Dumbledore] (PS12)
[Harry] discovers the [Mirror of Erised] and sees his family for the first timeOn the official timeline, this is 1991. Christmas in 1991 was on a Wednesday.
(PS12)
1992 (Y12) AD = 111 MM = 67 TR = 66 RH = 64 M = 34 BW = 22 CW = 20 PW = 16 FGW = 14 HG = 13 H&R = 12 GW = 11
[Norbert] hatchesThe calendar lists this date as April 24, but all we really know is that it is a few weeks before exams and that the weather gave the first hint of summer coming.
(PS14)
[Charlie]'s friends take [Norbert] from [Harry] and [Hermione] on top of the [Astronomy Tower]Unfortunately, they are caught by [Filch] - and given [detentions] by [McGonagall].
Derived from the estimated date of Norbert's hatching.
(PS14)
[Harry], [Hermione], [Neville], and [Malfoy] serve their [detentions] in the [Forbidden Forest]With [Hagrid] supervising, they track down a dead [unicorn]. [Harry] encounters [Voldemort] for the first time, and is saved by [Firenze].
We have no indication of when this date might be, except that it is shortly before final exams.
(PS15)
[Harry], [Hermione], and [Ron] follow [Quirrell] after the [Philosopher's Stone]They overcome the various protections, and defeat [Quirrell]/[Voldemort]'s attempt to steal the Stone.
The dates of this event are contingent on the dates of exams in [Harry]'s first year. We are given dates for exams in books two and three--the first week of June--but that doesn't seem to be a hard and fast rule. The calendar for this book gives the date as June 4, based on the exam dates in the other books, but here on the timeline we'll play it a bit safer and just go with "early June."
(PS16)
End of Term Feast[Gryffindor] wins the [House Cup], but not the [Quidditch Cup], which goes to [Slytherin].
(PS17)
The [Nimbus 2001] broomstick is released[Lucius Malfoy] soon buys them for the [Slytherin] Quidditch team. As it happens, [Draco] is made [Seeker] during the upcoming school term.
(CS7)
[Harry]'s 12th Birthday[Dobby] the [house-elf] visits [Harry] in [Privet Drive]. Meanwhile, the [Dursleys] are holding a dinner party for the [Masons], which is then disrupted when [Dobby] drops a violet pudding on [Mrs. Mason]'s head. [Harry] is sent a warning letter from the [Ministry], reminding him that he is not allowed to do magic outside of school ([CS1], [CS2]).
[Fred], [George], and [Ron] rescue [Harry] from the [Dursleys] in their father's [Ford Anglia]This is very likely the night of August 3, three days after [Harry]'s birthday. He arrives at the [Burrow], then, on the morning of August 4.
(CS2)
[Gilderoy Lockhart] announces that he is the new [Defence Against the Dark Arts] professor at [Hogwarts][Harry], who arrives at [Flourish and Blotts] just in time for the announcement, accidentally (and unwillingly) gets caught up in the publicity. Not long afterward, [Lucius Malfoy] and [Arthur Weasley] get into a scuffle, and [Lucius] drops [Voldemort]'s [diary] into [Ginny Weasley]'s [cauldron].
(CS6)
[Harry] and [Ron] miss the [Hogwarts Express] and fly [Mr. Weasley]'s bewitched car to [Hogwarts]They are spotted by several Muggles along the way and land, at school, in the [Whomping Willow] - subsequently landing them in a fair amount of trouble as well.
(CS5)
[Ginny Weasley], [Luna Lovegood], and [Colin Creevey] start their first year at [Hogwarts][Ginny] and [Colin] are sorted into [Gryffindor] and [Luna] becomes a [Ravenclaw]. [Harry] and his friends, meanwhile, start their second year.
(CS5)
The [Chamber of Secrets] is reopenedThis time the [Chamber] is opened by [Ginny Weasley], under the influence of [Tom Riddle], by means of his [diary]. [Harry] first hears the voice of the [Basilisk] during his [detention] with [Lockhart].
This is about a week into the school year, so it didn't take [Riddle] long to force [Ginny] to open the [Chamber].
(CS7)
The [Basilisk] from the [Chamber of Secrets] attacks its first victim: [Filch]'s cat, [Mrs. Norris][Harry] is discovered at the scene of the crime, and students start suspecting him to be the heir of [Salazar Slytherin]. [Harry] and his friends, meanwhile, begin to suspect [Draco Malfoy].
If we go by the calendar of this year according to the official timeline, Halloween is on a Saturday.
(CS8)
[Colin Creevey] is Petrified by the [Basilisk]The next morning, [Ron] and [Hermione] start working on brewing [Polyjuice Potion].
(CS10)
The [Duelling] Club[Harry] unwittingly uses [Parseltongue] to talk to a [snake] in front of the whole school; the [Hufflepuffs] in particular are now entirely convinced he's the heir of [Salazar Slytherin].
(CS11)
[Justin Finch-Fletchley] and [Nearly Headless Nick] are petrified by the [Basilisk][Harry] is taken to [Dumbledore's office] by [McGonagall], but when [Dumbledore] asks if Harry has anything to tell him, [Harry] says he doesn't.
(CS11)
Mr and Mrs Weasley visit Bill in Egypt
[Harry] and [Ron] use [Polyjuice Potion] to "become" [Crabbe] and [Goyle].They go into the [Slytherin] common room and learn that [Malfoy] is NOT the heir of [Salazar Slytherin].
(CS12)
[Hermione] is accidentally changed partially into a catShe spends the next month in the [hospital wing].
(CS12)
