Dates follow the Shire Reckoning, the hobbits’ own calendar, laid on our year so that each night falls on its day in the tale. Every Shire month has 30 days, so our 31sts have no Shire date, and a few days (Yule and Lithe) sit between the months. S.R. is the Shire year; add 1600 for the Third Age (S.R. 1418 is T.A. 3018), the reckoning used in the appendices.