30 May is the 150th day of the year (151st in leap years). There are 215 days remaining until the end of the year.
- 1744: Alexander Pope, a Muggle poet, dies.
- 1993: Lucius Malfoy is removed from the Board of Governors of Hogwarts School of Witchcraft and Wizardry. Albus Dumbledore and Rubeus Hagrid are permitted to return to their positions at the school. Dobby is freed, thanks to Harry, when Lucius unwittingly presents him with one of Harry's socks. An impromptu feast that began the previous night continues well into the morning.