Harry Potter characters make a lot of sense astrologically, which made me suspect that JK Rowling purposefully used astrology to create them. What's interesting is that, in the books, the only branch of magic that is mocked as bullshit is Divination because of Professor Trelawney.
When Trelawney is replaced by Firenze, read carefully. The astrological principles he teaches the students are pretty much textbook accurate. This makes it fun to look at the characters based on astrology. We won't get into it in this article but, when you look at the entire chart, you understand the characters even more. Let me know if you ever want me to do a detailed analysis of select Harry Potter characters. For now, here's an overview of one from each sign.
Aries: Fred and George
Yeah, they're Aries. They're red headed, brawny, and beaters. They're really annoying and play mean pranks on people for no reason. Fred is the mean twin and George is the nice one if you pay attention in the books but they primarily function as an unit. They don't function well under authority and they're always swearing that they're up to no good.
Their joke shop is also the only surviving business in Diagon Alley when the Death Eaters rise because they understand that, in the darkest of time, what people need is a good laugh. Since day one, Fred and George have been inventors. Aries likes to start new things, like their own business, whether said businesses succeed or fail. They're spectacular at quitting (see Fred and George dropping out of school during Umbridge's reign) but, fortunately, the joke shop turned out to be pretty successful.
Taurus: Horace Slughorn
Slughorn collects people as if they were commodities. When we meet him for the first time, we see that he's a guy who likes to be courted. This is Taurus, who likes to lay back and let others come to them because they know their worth. They like to idolize people and love to be idolized themselves.
The more we get to know Slughorn, the more we realize that he has a nose for money making opportunities and the finer things in life. He has a bottle of fancy alcohol that was originally intended for Dumbledore that he just can't resist drinking himself as soon as an excuse presents itself. He sneaks into Sprout's greenhouse and steals school property to sell on the black market. When Harry wins his affections, it's because he's found a way for Slughorn to collect a highly valuable type of venom first.
Gemini: Draco Malfoy
This is the Harry Potter character that most closely resembles Donald Trump. He's an archetypal schoolyard bully who believes in keeping the blood pure. Racism aside, Draco is pretty Gemini because we never see him make a decision of his own free will in the entire series.
He's a Slytherin because his family wants him to be. He's a Death Eater because Voldemort was playing some weird game. He ends up failing as a Death Eater because he can't make up his mind at the final moment.
Draco's saving grace is that he can't be totally a bigot and racist because there's just no possible way he'd be able to make up his mind long enough to believe in an ideology as elaborate as Voldemort's. He's not a savior or a bully in the end, but a nervous kid who is very human.
Cancer: Dudley Dursley
I actually really like Dudley. He's totally dependent on his family and the comforts of home. At school, he gathers his little clique. He's a total bitch to Harry because his parents are until Harry saves his life. Then, Dudley is really sweet to him. He's thoughtful enough to make Harry a cup of tea and leaves it right outside his door. Aww! Such a Cancer.
I believe that, in Dudley, we see what happens when a Sun in Cancer tries to handle toxic masculinity. Dudley is not brave. He's actually nurturing and he's the glue that holds him family together even when his dad is such a nasty person.
Dudley's flaw is that he is reluctant to leave what he knows. He hates Harry because he represents something that can wreck his illusion of a comfort zone. We see a lot in Harry PoV in the books but we have to remember that Dudley is getting constantly fat shamed by his cousin so hit makes sense there's a lot of beef between them.
Leo: Harry Potter
Yeah, Harry is a Leo, the archetypal hero. JK Rowling actually gave him her own birthday so he is JK Rowling in some ways. Harry is a true Gryffindor. He's willful, wants to do things his own way, and wants to save everyone.
It's hard to see how much of a Leo Harry is because the whole story is told through his eyes but remember that this is a boy who, by virtue of being born, fulfills a prophecy that saves the entire wizard population. The story of Harry Potter is basically the story of a royal or aristocratic prince, just set in modern times.
The train ride to Hogwarts symbolizes a return to a more pastoral England, one that was feudal in economy. The type of hero Harry is comes ultimately from this English literary tradition. He's a prince, born to be a king, just with a little postmodern deconstruction thrown in.
Virgo: Hermione Granger
I mean, she likes the smell of spearmint. And she spends all her time in the library, researching archaic things. Hermione's favorite time is the beginning of the school year and her favorite smell is the smell of old books.
Hermione loves figuring things out. She can solve puzzles, brew potions, and all of that. She knows ancient runes and took on twice the class load of a typical student in her third year voluntarily.
Another thing that is so Virgo about her is that she's very independent in affairs of love even with her first boyfriend. She kept Victor a secret from her friends successfully for a long time and compartmentalized time with him. When it came time to break up, he was definitely more heartbroken than she was. For Hermione, a relationship didn't really change who she was. She remained always herself.
Libra: Minerva McGonagall
McGonagall is the keeper of law and order at Hogwarts. There's no one there with as much good sense as she. And whatever happens at school, even when the whole thing was overtaken by Death Eaters, McGonagall kept it classy.
Unlike the more outspoken male characters around her, McGonagall doesn't just charge first and think later at things she doesn't like. She has a way of making biting comments from a completely detached standpoint that no one can fault her on. When she tells Umbridge to be quiet in her class, she's the only one that actually has an affect on the soon to be Headmaster. When Harry is sent to her office for yelling at Umbridge, she mysteriously tells him to have a biscuit.
Though McGonagall is obviously one of Dumbledore's, her ability to stay detached and superficially diplomatic until an emergency arises let her stay at Hogwarts while many others were prosecuted. Everyone knew to not mess with McGonagall, because there was always something for her to get you for instead.
Scorpio: Sirius Black
He's the black sheep of his family and the black sheep of the Order of the Phoenix. There's not a place in the world for Sirius Black. The guy has a secret identity and stays in hiding for the entirety of his life.
It's subtle how much Sirius seems to have been distrusted by the Order, even before James and Lily were killed. He seems to not have trusted himself very much, since he himself suggested Peter Pettigrew for secret keeper over himself, though Peter was a pretty suspicious dude. The night Voldemort's curse rebounded, we see Hagrid bring Harry to the Dursleys on Sirius's motorcycle, meaning that it wasn't immediately apparent to them who had betrayed the Potters.
This makes us wonder a little about just why Sirius became the scapegoat he did and was sent to Azkaban for it. Even his best friend, Remus Lupin, believed that he was guilty. This definitely isn't a guy who knows how to build trust with his friends.
Sagittarius: Rubeus Hagrid
Hagrid goes to extremes over everything. He has no sense of danger, will eat anything, and sees monsters as pets. This isn't because he's a giant, as we see another giant behaving entirely differently. It's because he's a Sagittarius.
This guy is the worst at keeping a secret. Harry and the golden trio learned early that if you want information that the adults are keeping from you, Hagrid's hut is the place to be. Sagittarius is the sign of publishing and no Sagittarius can ever keep a secret for very long.
So, Hagrid is more than a lovable giant. He's a reckless gambler of life. We see him lose big, win some, and come out about even in the end. He's one of the most superstitious people in the books too, preferring to keep the Dark Lord's name away from his mouth at all costs.
Capricorn: Severus Snape
Well, both Voldemort and Snape are Capricorns but I chose Snape to write about since technically Voldemort is no longer human. Snape is a little like Shrek. He has a lot of layers. He knows how to work his way into an organization, whether it's the Order of the Phoenix or the Death Eaters. He's capricious and severe as a teacher.
Rather than doing anything for heroism, Snape does the dirty work of the organization. He's the one who needs to do the killing that is needed and willing to take the blame when the time is right. He knew that he would die for his cause from the onset.
Snape is also a character that plans things out really well. He hates Gryffindors because he sees them take all the glory once what's needed to be done is done. Rather than showing off, Snape prefers to execute his plans in hiding and carry them out strategically.
Aquarius: Luna Lovegood
Luna is your basic manic pixie dream girl. She's really weird, really pretty, and a great choice of a date for a Slughorn party when you want to make a point of being too eccentric into proper society. She'll believe anything as long as it's a conspiracy but once your cause falls into the political mainstream, she'll fall into the sidelines.
While Aquarius likes to pretend to not care about social status, their position as an outcast is actually one that takes a lot of intentionally maneuvering and careful analysis of social systems. Eccentricity is actually a classic trope that marks someone as aristocratic in an European literary tradition, popular during the days of A Rebours and Dorian Gray.
Luna's most useful role is as a person Harry can project his own feelings of being misunderstood on, whether that's because he's ostracized as in the fifth book or too glorified by those with tacky taste, such as by Slughorn's value system. The reason she works in the role is because of the European traditional of seeing eccentricity as better than thou.
Pisces: Ron Weasley
Most of the time, we get the sense that Ron doesn't really understand what's going on. He has no idea why they're going to the third floor in Sorcerer's Stone, no idea that he's in love with Hermione, and goes through his entire second year with a wand that doesn't work without anyone noticing. He is grade A clueless.
The first thing Ron notices about Harry is that he's Harry Potter. Pisces love a little glamor in their lives and Ron wants desperately to rub shoulders with someone famous. He's similarly enchanted with Victor Krum, at least at first, and obsessed with the Chudley Cannons. Pisces is a sign that loves to be a fan because they love escaping into an alternate world.
Pisces is also a great underdog and that's Ron's role both in his family and in every one of his relationships. He's easily tricked into almost anything. We cheer when he and Hermione get together because, by god, he needs someone to keep it together for him.