I whipped up these calendars based on Appendix D of LotR, starting with the Westron calendar and then making a "conversion" to the Shire calendar where the columns correspond to the same days on both. That's why some of months on the Shire calendar end with the 1st of the next month, or begin with the 30th of the previous (makes it easier for players using different calendars to track the passage of time, IMO). In other words, the day that corresponds to the top of the May column is May 2nd in the Shire, but May 1st everywhere else. Another example being that the top of the Oct column is not Oct 1st on either of the calendars; it's Sep 30th in the Shire, and yáviérë in the Westron calendar.
Which leads into my next point. Because every month on both calendars contains 30
days, there are 5 "leftover" days. In both cases these days are not
counted as being a part of any month, but are holidays. The biggest
discrepancy between the 2 calendars stems from the fact that the
holidays in the Westron calendar fall on the first and last days of the
year, the middle day of the year (midsummer), and between Mar/Apr and
Sep/Oct, whereas in the Shire calendar the first and last days of the
year are Yule, and the remaining 3 holidays are all grouped together in
midyear and referred to collectively as "lithe" (with the middle day of
lithe being midsummer, or loëndë on the Westron calendar).
leap years the Westron calendar lacks loëndë, instead having 2 enderi
(middle days). In the Shire the extra day is added after the 2nd
lithe-day, and is called Overlithe (which is a day of special
merrymaking). Year 4 T.A. was a leap year, which makes the first
in-game leap year for TOR 2948.
The main use that I see
these calendars having is for Loremasterss and/or players (if they're
inclined) to check off days as they pass in-game. I would probably
strike a line through the columns when long periods of game time pass,
such as during uneventful journeys or during Fellowship phases. Perhaps
too book-keepy for some groups, but given how much emphasis Tolkien
placed on the passage of time I think it's an appropriate way to