Bilbo and Frodo's Birthday (Observed)

Tolkien made September 22, the day on which the first copies were purchased and read, Bilbo's and Frodo's birthdays, and the American Tolkien Association has designated as "Tolkien Week" the week in which September 22 falls. --The 1938 Hobbit Project

How the date of Bilbo's (and Frodo's) birthday corresponds with our calendar is a matter of debate. Appendix D of The Lord of the Rings says that our New Year's Day (January 1) corresponds "more or less" to the Shire's "January 9", and in standard years our September 14 and the Shire's "September 22" both fall 256 days after that date. However, Appendix D also says that the Shire calendar's "Midyear's Day" is "intended to correspond as nearly as possible to the summer solstice." In the Shire calendar, "September" (Halimath) 22 is 83 days after Midyear's Day. If we take the summer solstice to be our June 21, then Bilbo's and Frodo's birthday must be 83 days later, which is our September 12. --Footnote from Tolkien Gateway