The Harry Potter novels took place throughout the '90s, though this rarely came up in the story. It's not like Harry ever suddenly became really interested in a hot new band called Nirvana, while Ron became skilled at Wizard Pogs and Hermione started quoting Wayne's World.  The fact that Harry Potter spent most of his time around wizards meant that Muggle culture rarely came up, so the fact that the story was set in the '90s didn't mean much in the grand scheme of things.

J. K. Rowling didn't keep a close track of calendars of the Harry Potter world, nor did she pay much attention to the technology and trends of the period, which meant that a lot of timeline issues crept into the series as it progressed.

The Harry Potter movies had an even more difficult time avoiding anachronisms, as the timeline was meant to be the same as the novels, yet they had to film in the physical world of the '00s. We are here today to explain why the timeline of the Harry Potter books and movies doesn't make any sense; from Dudley's uncle who works at Sony who bought him a PlayStation a year early, to the mystery of the Muggle Prime Minister.

Here are Twenty Reasons The Harry Potter Timeline Makes No Sense!

20 Dudley Had A PlayStation Before They Were Available In The UK

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At the beginning of Harry Potter and the Goblet of Fire, Harry is staying over at Privet Drive before the start of his fourth year at Hogwarts. This was during the summer of 1994.

Dudley Dursley had been forced to go on a diet by his parents, which Harry noted had caused him to lose control of his anger and throw his original PlayStation out of the window. The problem with this scenario is that the PlayStation wouldn't be released in Europe at the time he supposedly had it, and wouldn't even be released in Japan for a few more months.

19 The First Day In The First Book Was Incorrect

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J. K. Rowling has freely admitted that maths isn't her strong suit, which is partly why Quidditch makes so little sense. The other thing that J. K. Rowling can't get her head around is dates, as the Harry Potter timeline makes no sense.

The dates of the Harry Potter don't match up to the real world, nor do they follow their own consistent framework. The issues with the dates in Harry Potter started with the first chapter of the first book, as it is said to take place on the 1st of November in 1981, which is described as being on a Tuesday. This doesn't match up to the real world calendar, as the 1st of November 1981 fell on a Sunday.

18 Harry & Hermione Dance To A Song That Hasn't Been Released

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There is a scene in Harry Potter and the Deathly Hallows: Part 1 where Harry and Hermione dance together to a song called "O Children" by Nick Cave and the Bad Seeds. This scene seems to have only been added to placate the wounded souls of the Harry/Hermione shippers around the world, who had their hearts broken by the final book in the series.

The problem with this scene is that the song "O Children" wouldn't exist for a few more years. The events of The Deathly Hallows take place in 1997, but the album that "O Children" was released on (Abattoir Blues/The Lyre of Orpheus) wouldn't be released until 2004.

17 Harry & Ron Pass The Wrong Tower

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In Harry Potter and the Chamber of Secrets, Harry & Ron are prevented from entering Platform 9 3/4 by Dobby, so they decide to use the magic Ford Anglia to fly to Hogwarts. The invisibility spell that protects the Ford Anglia is faulty, which means that several Muggles spot the car as they fly past. When the boys arrive at Hogwarts, they are told that they were seen flying past the Post Office Tower.

The problem with this line is that the Post Office Tower had its name changed to the BT Tower in 1984. The BT Tower is also south of King's Cross station, which means that Harry and Ron would have been flying in the opposite direction.

16 Lupin Should Have Been Too Ill To Meet Harry On The Train

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The first time that Harry Potter meets Remus Lupin is during the train journey to Hogwarts before the beginning of his third year of study. A Dementor arrives on the train, causing Harry to pass out, but Lupin manages to scare it off.

The problem with Lupin's presence on the Hogwarts express that day was that it took place on September 1st, 1993, which was a day in which a full moon was in the sky. Lupin should have been far too ill to have taken the train to Hogwarts, as it was stated that he couldn'teach for three days precending the full moon due to his condition.

15 Harry & Dudley's 11th Birthdays Took Place On The Wrong Days

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Harry Potter was born in the same year as his cousin, Dudley Dursley, with Harry's birthday falling on July 31st, while Dudley was born on June 23rd. We see both Harry and Dudley's eleventh birthdays during the events of Harry Potter and the Philosophers Stone, but they take place on incorrect dates.

Dudley's birthday party & trip to the zoo takes place on a Saturday, even though June 23rd in 1991 was a Sunday. Harry Potter's birthday was said to take place on a Tuesday, even though July 31st in 1991 was a Wednesday.

14 The Death Eaters Mess With The Millennium Bridge Before It Existed

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When Voldemort openly revealed his presence to the wizarding world and enacted his plan to take over the Ministry of Magic, he sent his Death Eaters out to capture those with knowledge of the Elder Wand.

In the movie version of Harry Potter and the Half-Blood Prince, we see the Death Eaters toppling the Millennium Bridge in London, while people are trying to walk across it.

Harry Potter and the Half-Blood Prince takes place in 1996 and the Millennium Bridge wasn't open to the public until the year 2000, as you could probably tell by the name.

13 The Death Eaters Hung Out Together At Hogwarts (Even Though They Attended At Different Times)

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The ages of some of the actors in the Harry Potter movies are different from those in the books. Severus Snape was in his mid to late thirties throughout the events of the books, yet Alan Rickman was in his mid-fifties when production on Harry Potter and the Philosopher's Stone began.

Bellatrix Lestrange is almost ten years older than Severus Snape in the books, which you wouldn't be able to tell from the movies. The ages of Bellatrix and Snape actually caused a contradiction in the books, as Sirius Black tells Harry that Bellatrix and Snape ran in the same crowd, yet Bellatrix graduated a year before Snape started at Hogwarts.

12 Fred & George Received Their O.W.L. Results Too Early

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Fred & George Weasley weren't skilled in academics, but they still managed to create a thriving business after they left Hogwarts, with a little help from the gold that Harry won as a prize from the Triwizard Tournament.

It's revealed at the end of Harry Potter and the Prisoner of Azkaban that Fred & George earned a few O.W.L.s each. They received their results in June while the school year was still going on, even though later books established that O.W.L. results were sent by an owl during the month of August, which happened during the summer holiday.

11 Harry's Astronomy Exam Makes No Sense

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The O.W.L. exams take on many different forms, with a mixture of practical work and written tests that are used to gauge the skills of each student.

The Astronomy O.W.L. exam involved filling out a star chart from information gleaned from looking up the night sky through a telescope.

When Harry Potter takes his Astronomy O.W.L. exam, it is mentioned that he saw Venus at 12:00 am, even though Venus can never be seen around midnight. Venus can only be seen shortly before sunrise or shortly after sunset.

10 The Dursley's Car Has A 2006 Licence Plate... In The '90s

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The role of the Dursleys in the Harry Potter movies was greatly diminished from that of the books to the point where several films just skipped them entirely. It was probably for the best that the Dursleys were left out, as their connection to the Muggle world caused several anachronisms, as we will see later on.

In Harry Potter and the Order of the Phoenix, the scene where Dudley is attacked by the Dementor is integral to the plot, so the Dursleys had to appear in the story. We are given a glimpse at the Dursleys' car, which has a 2006 registration plate, even though the start of the movie is supposed to take place in 1995.

9 The Valentine's Day Incident Happened During Sunday Classes

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The movie version of Harry Potter and the Chamber of Secrets may be the most accurate adaptation of any of the books, with almost every plot point being covered.

One of the events from Harry Potter and the Chamber of Secrets involved Gilderoy Lockhart hiring dwarves to dress in cupid outfits so that they could hand out cards & gifts on Valentine's Day, which ended up interrupting classes. The problem with Lockhart's Valentine's Day stunt was that it happened in 1993, which was a year when Valentine's Day took place on a Sunday, so no classes should have been on.

8 The Dursleys Owned A Flat-Screen TV... In 1995

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J. K. Rowling has revealed tidbits about what happened to the Harry Potter cast after the events of The Deathly Hallows during interviews and on her Twitter account.

We know that Vernon Dursley was a fan of the TV show Top Gear, as Rowling stated he signed an online petition to bring Jeremy Clarkson back to the show, as he was the only reason he watched it. Vernon Dursley's love of television may explain why he has a flat screen television in 1995, even though they weren't commercially available until 1997, when they cost around fifteen thousand dollars to buy.

7 The Mystery Of Ogg & His Time At Hogwarts

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Rubeus Hagrid was expelled during his third year at Hogwarts, as Tom Riddle framed him for the crimes committed by the basilisk within the walls of the school. Hagrid had his wand snapped and was forbidden from performing magic again, but Albus Dumbledore ensured that Hagrid was hired as the Gamekeeper of the school.

Molly Weasley would go on to create an inconsistency with the timeline when she mentions in Harry Potter and the Goblet of Fire that the Gamekeeper of Hogwarts was a man named Ogg. Hagrid was expelled & made Gamekeeper long before Molly attended Hogwarts, so he should have been the Gamekeeper during her time at the school.

6 The Events Of Merlin's Life Make No Sense

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Merlin is a significant figure in the history of the Harry Potter universe, as he served King Arthur and became an important figure to both Muggles and wizards alike, to the point where the most prestigious award given to wizards (the Order of Merlin) is named after him.

The problem with the history of Merlin is that it doesn't make sense. Merlin was said to have served King Arthur at some point during the late 5th to early 6th century, and he was also said to have studied at Hogwarts, which wasn't established until 993.

5 Harry Flew Past The London Eye Before It Existed

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Hogwarts is located somewhere in Scotland, but most of the time spent among Muggles in the story of Harry Potter happened in the city of London. Filming scenes in London for the Harry Potter movies was always going to be an issue in terms of creating historical anachronisms, which is likely why the film-makers never worried about them too much.

One instance where filming in London caused a chronological hiccup was during a fly-by scene in Harry Potter and the Deathly Hallows: Part 2, as the London Eye appears in the background. The Deathly Hallows: Part 2 is meant to take place in 1998, which was when construction on the London Eye had only just begun.

4 The Cars In Privet Drive Were Made In 1999... In The Year 1991

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We never saw much of the Muggle world in Harry Potter, with the bulk of the books taking place in and around Hogwarts. The most we see of the non-magical world happens during Harry's time at Privet Drive over the summer.

The first Harry Potter movie shows us Privet Drive as it's being bombarded with letters from Hogwarts. There's a scene where we see lots of owls sitting outside of the house, much to the despair of the Dursleys. All of the cars shown on Privet Drive are Vauxhall Vectra Estates, which were not made available to the public until the year 2000, even though the start of Harry Potter and the Philosopher's Stone takes place in 1991.

3 The Daily Prophet Newsletters Make No Sense

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One question that a lot of Harry Potter fans had when the series was still being written was if J. K. Rowling had everything planned out or was just winging it as she went along?

In 1998, J. K. Rowling created small issues of The Daily Prophet as newsletters that were distributed to members of The Harry Potter Fan Club. Four of these newsletters were created over the course of two years.

The Daily Prophet newsletters include tidbits about the future of the series that don't gel with the events established by Harry Potter and the Deathly Hallows. The most egregious of these was Cornelius Fudge still being the Minister of Magic in 1999, as he used his connections to keep his nephew out of trouble and planned to restrict festivities during Halloween.

2 The Gryffindor Students Listen To A Song That Won't Be Released For Another Decade

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The Harry Potter novels almost never mentioned the musical tastes of the characters, with the exception of most witches & wizards being a fan of Celestina Warbeck.

Harry Potter and the Order of the Phoenix included a scene where Harry enters the Gryffindor and has an argument with Seamus Finnegan, while the song "Boys Will Be Boys" plays in the background. "Boys Will Be Boys" was a song by The Ordinary Boys which was released in 2005, which means that it was released a decade after the events of Order of the Phoenix, which transpired in 1995.

1 The Mystery Of The Identity Of The Muggle Prime Minister

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Harry Potter and the Half-Blood Prince revealed that the Muggle PM of the United Kingdom was made aware of the existence of wizards when they entered office. We briefly see the current PM when he is introduced to Rufus Scrimgeour for the first time. It's not made clear who the Muggle PM, as he never gives a name throughout the one chapter that he appears in.

There is contradictory information over who the Muggle PM is. By the official timeline, it should have been John Major, but he mentions that his predecessor was a male, while John Major's predecessor was Margaret Thatcher. The Muggle PM more closely resembles Tony Blair, who won the seat in 1997. This suggests that J. K. Rowling created an amalgam of the two, possibly in an attempt to avoid criticisms of either of the two leading parties in the United Kingdom.