A timeline do Tolkien Gateway comenta que a festa de 111 anos teria sido em 3001 em setembro, (ano 1401 na contagem do condado). A batalha ocorreu pouco tempo de Bilbo conseguir o anel nas montanhas (Bilbo se torna o membro catorze da comitiva em 2941 (ano 1341 no sistema do condado)
http://tolkiengateway.net/wiki/Timeline/Third_Age
[edit] Bilbo's Farewell Party
At last, in September of
3001, Bilbo threw a
grand party for his 111th birthday (which happened to be shared with Frodo). During this party he did a vanishing act with his ring and left with three dwarves for
Rivendell, to live with
Elrond and the elves there. He only took with him a
book that he was composing, his sword
Sting, his
mithril coat, and a dark green hood and cloak which had been given to him by
Dwalin years before. He wanted to take the ring with him as well, but upon the urging of Gandalf, left it behind for Frodo, along with
Bag End and the rest of his possessions. Bilbo was the first ringbearer to give up the One Ring in this way.
Thus the Hobbit became the fourteenth member of
the Company which left the Shire in
T.A. 2941.
[4].
Dados precisos sobre dias e meses da batalha ficam em aberto (A Karen do Atlas da Terra Media especula em 23 de novembro) usando talvez uma estimativa feita com base em manuais de marcha das forças armadas (que o Tolkien usava pra fazer os livros) e detalhes do clima que pudessem aproximar a estação do ano. Mas novamente, especulativo, conforme o site TG explica.
Por exemplo, A Karen coloca o Dia de Durin (semanas antes da guerra quando penetram na toca de Smaug) em 30 de outubro, o Andrea Mohn, baseado em ciclos lunares coloca em 22 de outubro.
...
Unlike
The Lord of the Rings Tolkien left no precise timetable for the events of
The Hobbit. However, in
The History of The Hobbit, Tolkien set
19 October as the date of that year's
Durin's Day.
[2]
Before the
History some calculations were made. According to
Andreas Möhn, the Durin's Day of
T.A. 2941 occurred on
22 October of the
Shire Calendar. This is based in the assumption that the orbital period of the moon, as described in
The Lord of the Rings, was about 20 minutes shorter/faster than today.
[3]
Karen Wynn Fonstad made a rough estimation based purely on the traveling times and distances, without any astronomical calculations. She puts the Durin's Day on
30 October.
[4]
...
@MariDin