We hear about Harry’s birthday frequently, often at the start of each book to anchor us in terms of where we are in time. His date of birth also, of course, plays a role in the prophecy that cause Voldemort to mark Harry with his lightning scar.

Dudley Dursley’s birthday occurs on June 23rd, and is actually the very first Harry Potter birthday we encounter in the books. But some have felt, basically by seeing certain alleged manger scenes, that the Magi/wise men came from the East and gave Jesus presents on the day of His birth,” -[Should Christians Celebrate Birthdays?: Do Birthdays Have Pagan Origins?, Bob Theil].Christmas is also relevant because December 25th was the day of celebration of the birthday of the sun-god Mithra. Perhaps it should also be mentioned that one of the key features of Mithraism was Sunday observance. The reason that this seems to be relevant is that the Roman Emperor Constantine, the first Roman Emperor to make a profession of Christ, was also the first Emperor to make Sunday laws–which he began to do on March 7, 321. Also, a few years later, the Council of Nicea that Constantine convened in 325 A.D. declared Sunday to be the “Christian day” of worship (for more information, please see the article Europa and the Book of Revelation).” Allah’s Apostle, may Allah’s peace and blessings be on him said: ‘There is none amongst you with whom is not an attache from amongst the jinn (devil). They (the Companions) said: Allah’s Apostle May Allah’s peace and blessings be on him with you too? Thereupon he said: Yes, but Allah helps me against him and so I am safe from his hand and he does not command me but for good’”, –[Sahih Muslim 6757, similar narration 6759 by 'Aisha, radyAllahu anha].

Since it was believed that the positions of the stars at the time of birth influenced a child’s future, astrological horoscopes came into being, purporting to foretell the future, based on the time of birth. “Birthdays” are intimately linked with the stars, since without the calendar, no one could tell when to celebrate his birthday. They are also indebted to the stars in another way, for in early days the chief importance of birthday records was to enable the astrologers to chart horoscopes,” [The Lore of Birthdays, p. 53].Rowling occasionally likes to Tweet out her birthday wishes to characters and encourage fans into supporting her rugby team with promises of sharing more. It is worth noting that Snape, James Potter, Lily, and their other contemporaries at Hogwarts should only have been 31 or 32 during the events of the first Harry Potter movie, but they are all portrayed by significantly older actors.