The Shire Calendar was used by the Hobbits of the Shire. It was different from that used by the Men, Dwarves and Elves. Use of this calendar in Middle-earth is referred to as Shire-reckoning.
The calendar featured 12 months, all 30 days long, plus 5 or 6 named days added to round out 365 days (or 366 for leap years). Two of the named days were Yuledays; one was the first day of the year and the other was the last day of the year. Between June and July were the Lithedays. In common years (not leap years) there were three: 1 Lithe, Mid-year's Day, and 2 Lithe. In leap years (every fourth year except in the last year of a century) an extra Overlithe Day was added after Mid-year's Day. All of the named days were major holidays (and a reason for feasting) with Overlithe being a day of special merrymaking.[1][2] The two Yuledays were actually a portion of Yuletide, which included the last three and first three days of each year.[2]
In The Hobbit and The Lord of the Rings, the names of months and days are given in modern equivalents. For instance, Afteryule is called January and Sterday is called Saturday.[2]