In Shakespeare’s Romeo and Juliet, Juliet’s birthday is traditionally associated with July 31.
The Nurse says Juliet was born on Lammas Eve, the evening before Lammas Day. In the play’s traditional calendar, Lammas Day falls on 1 August, making Juliet’s birthday 31 July. The date is mentioned during the Nurse’s recollection of Juliet’s childhood and helps establish that Juliet is nearly fourteen.
This detail is easy to confuse because Lammas Eve is sometimes treated as the evening of 1 August in modern discussion, and calendar customs varied historically. In the play’s wording, however, the Nurse specifically places Juliet’s birth on the eve of Lammas.
Juliet’s birthday is also significant because the Nurse’s memories are domestic and affectionate, contrasting with the public feud and political violence surrounding the young couple. The date is not the date of the Capulet feast or the wedding.