J.K. Rowling’s birthday is 31 July, the same date given for Harry Potter’s birthday.
Rowling was born Joanne Rowling on 31 July 1965 in Yate, Gloucestershire, England. Harry Potter’s birthday is also 31 July, a deliberate connection between the author and her central character. The date appears in the first novel, Harry Potter and the Philosopher’s Stone, when Harry learns that he is turning 11.
The shared birthday is one of several autobiographical or personal links readers have noticed in the series, although Harry is not a direct self-portrait of Rowling. Rowling has said that the idea for Harry Potter came to her during a delayed train journey from Manchester to London in 1990. She then developed the characters and story over several years.
A common mix-up is to confuse Harry’s birthday with Halloween, which is important elsewhere in the plot. Halloween is the anniversary of Voldemort’s failed attack on Harry, but it is not either character’s birthday.