Buffy The Vampire Slayer

Birth of the Buff

In 4.11 Doomed, Buffy says that she’s a Capricorn on the cusp of Aquarius, which confirms that her birthdate is somewhere between the 17th and the 20th of January. This corresponds to the fact that her birthday episodes usually air that week in the US (usually the 18th or 19th episode of each season).