Discworld calendar

A Discworld celestial year has 800 days and because of some interesting astronomical facts two of each seasons (two summers, two winters, etc.). This leads to the fact that many people actually do not count the astronomical years, but the half-years with 400 days, often refered to as "common years". The half-year has 13 months, listed below. Each month except Ick has 32 days, Ick has 16 days. Each week has eight days. The eighth day of each week is called Octeday.

There are two main calendars in use on Discworld. The Ankh-Morpork Calendar counts full years and starts at the founding of Ankh-Morpork, the University Calendar starts at the founding of Unseen University (in 1282 AM) and counts in half-years. Oddly enough, while the Imperial Ankh-Morpork calendar offers intellectual purity and mathematical elegance, the general populace tends to use the Weird, Wild, Wacky Wizards' calendar, which happens to correspond to the growing season.

Centuries and years are named. We are currently in the Century of the Anchovy (Carpe Jugulum). It was preceded by the Century of the Fruitbat (Moving Pictures) and even earlier by the Century of the Three Lice, and the Century of the Cobra (Small Gods).

In Feet of Clay Doc Pseudopolis, President of the Guild of Gamblers, says “in a few years it’ll be the Century of the Rat.” No-one objects to this, but subsequent Discworld novels that mention the century refer to the Century of the Anchovy, perhaps suggesting that centuries are not named that far in advance (and that this is a bet Doc has lost).

• The Century of the Summer Weevil (mentioned in Unseen Academicals)
• The Century of the Dragonfly (mentioned in Reaper Man)
• The Century of the Cobra (mentioned in Pyramids)
• The Century of the Three Lice (mentioned in Reaper Man and the Discworld Roleplaying Game)
• The Century of the Fruitbat (mentioned in Reaper Man, Men at Arms, Moving Pictures, Small Gods, Lords and Ladies, Carpe Jugulum, The Fifth Elephant, The Truth,