The Calendar of Imladris was a calendar used by the Elves of Rivendell. (Imladris is the name of that land in Sindarin.) It is apparently the only Eldarin calendar described by the Hobbits in the Red Book of Westmarch.
Summer and winter both lasted for 72 days; the other seasons were each 54 days long.
In every idhrinn there were five additional days that were not considered a part of any season and were celebrated as holidays. Between Autumn and Fading were three middle-days called enedhoer (translated from the attested Quenya name enderi). They were named Ethuilor "Spring-day", Inenedh "Year-Middle" (Mid-Year's Day according to the calendar of the Elves), and Iavasor "Harvest-day" (translated from the attested Quenya names). The first day of the year was Maninor "First Year-day" (translated from Quenya), and the last day of the year was Penninor "Year-full Day".
This produced an idhrinn of 365 days, but to keep a deficit of minutes from building up over time, every 12th idhrinn had double-middle-days (so six instead of three, the Elvish equivalent of a leap-year) to get an �n of 144 idhrinn. Then every third �n had to be shortened by three days - eliminating the doubled middle-days one time - to adjust the calendar yet again!
The Seasons Edit
|Season name (Quenya)||Season name (Sindarin)||English translation|
|quellë ||firith ||fading|