Exalted presents a calendar of its own, and I've made certain changes to it to suit my own sensibilities. But I've failed to nail down these changes in a handy location for reference, so they keep mutating when my back is turned. This is an attempt to settle the system that I'm using, once and for all.
I also elaborate a bit on the practices and traditions relating to the calendar, and detail the Underworld's calendar a bit.
The Imperial Calendar is a true Lunar calendar … that is, the months match the lunar cycle of 25 days (five weeks with five days each). There are fifteen months in the year, divided into five seasons. There is also a five-day Calibration period which is not part of any month.
Thus, the year is 380 days long. To turn an Earth age into the equivalent in Exalted years, multiply by 0.96. (To do the same for the canon Exalted calendar, which is 425 days long, multiply by 0.86)
It may help the following explanation to look at the final result
Days and Nights (except during Calibration) are always the same, equal length.
The five days of the week are named for their associations with the Five Maidens (though not in the usual order), and each day has a particular favored activity:
Mercurysday - Best day to start a journey (physical or metaphorical). Sometimes shortened to “Mercsday”
Jupiterday - Best day to take care of private business. Sometimes shortened to “Juday”
Marsday - Best day to fight a battle
Saturnday - Best day for funerals and memorials, best day to end tasks. Sometimes read “Saturday”
Venusday - Best day for a festival or wedding. Sometimes shortened to “Vensday”
The typical workweek consists of Mercuryday through Saturnday, with Saturnday marking the death of the workweek as befits the maiden of endings. Venusday is thus a day of rest.
There are five seasons, named after the elements they are tied to: Water, Wood, Fire, Earth, and Air (in that order). Roughly, these equate to: The rainy/storm season, Spring, Summer, Fall, and Winter.
(Note that the elemental associations are modified from the canon calendar. This is because the Elemental Pole of Air — not Water — seems most clearly associated with cold and ice, the Element of Water suits rain, and the element of Earth is associated with farming and harvests … and thus, autumn, plus barrenness.)
Each season contains three months, which serve as the phase of the season. These are called Ascending (when the element is gaining strength), Resplendent (when the element is at its peak), and Descending (when the element is losing strength).
Thus, Resplendent Air is the coldest month, Resplendent Water is the rainiest month, Resplendent Wood is the most verdant month, Resplendent Fire is the hottest month, and Resplendent Earth is the height of Autumn.
Dates are written with the number first, e.g., 18 Resplendent Fire.
There are 5 regular phases of the moon. They occur as follows:
1st to 3rd - Waxing Crescent Moon
4th to 5th - Half Moon
6th to 7th - Waxing Gibbous Moon
8th to 13th - Full Moon
14th to 15th - Disseminating (Waning Gibbous) Moon
16th to 17th - Half Moon
18th to 20th - Balsamic (Waning Crescent) Moon
21st to 25th - No Moon
Taken together, the Waxing, Waning, and Half moon phases are called the Changing Moon (thus the Lunar caste).
Eclipses, special conjunctions of the Unconquered Sun and Luna together (thus considered phases of both), occur regularly only during Calibration.
Calibration is the five-day period that falls between Descending Earth and Ascending Air, and is roughly analogous to Halloween, Friday the 13th, and Mexico's Día de los Muertos, all at the same time (the emphasis varies from region to region, however).
There will always be at least one eclipse during Calibration. Calibration eclipses are always total eclipses, and usually occur near the start or the end of the five days (but can occur any time during). They can last anywhere from a handful of minutes up through the entire five-day period. The length of an eclipse is tied to its rarity (in other words, five day eclipses are far less common than 7 minute eclipses). Longer eclipses are also seen as stronger omens. There is no moon at night during Calibration.
The Calibration of Realm Year 763 (the year the Scarlet Empress disappeared and the Solar Anathema began returning) was a three-day-long eclipse. The Calibration of Realm Year 768 (which coincided with the fall of Seven Willows) had an eclipse only a day long, but it was also marked with an unusual arrangement of the five maidens (in a circle surrounding the eclipse) and a number of other portents. Other lengthy eclipses presaged the Fall of the Solar Deliberative and the coronation of the Scarlet Empress
Other odd astronomical events can also occur during Calibrations: the sun refusing to rise or set, or hovering just at the horizon, variations in the normally regular length of day or night, meteor showers, false sunsets, etc.
Aside from Calibration, brief eclipses (usually only a few minutes in duration) typically occur up to twice a year, at some point during the week of the new moon, but predicting these events is best left to astrologers. These eclipses can be partial or total eclipses.
The full moon of each month has a name. From the beginning:
Water: The Glittering Moon, The Silver Moon, The Mud Moon
Wood: The Planting Moon, The Green Moon, The Flowering Moon
Fire: The Hare Moon, The Flame Moon, The Wolves' Moon
Earth: The Fey Moon, The Harvest Moon, The Darking Moon
CALIBRATION
Air: The Snow Moon, The Ice Moon, The Shimmering Moon
Several of these tend to somewhat resemble their names (i.e., the Green Moon has a slight greenish tinge, the Shimmering Moon seems ephemeral and dreamlike, etc.)
Another special lunar event that can occur occasionally through the year is the Bloody Moon (not to be confused with the Bloodmoon). It is also known as Moonshadow. This is when the usual moon turns blood red for a period of time (no more than an hour). This most frequently occurs during the Full Moon, but can actually occur during any phase (except No Moon). This is said to be Luna remembering her actions in the Gods' War, the color alternately said to be in honor of Umbra, a curse laid by him, or simple guilt and embarassment.
The months, days, weeks, and seasons of a single year are typically marked on a wheel-shaped calendar, which can be wall-mounted or placed flat like a table, free-turning or fixed in place. This wheel can be constructed of stone, metal, wood, or even paper, according to the wishes and resources of the owner.
Calibration is not marked on most calendars. Instead, the wheel is usually covered in velvet or silk (usually black) for the duration, or even (in more superstitious/ritualized households) broken or burnt at the start of Calibration, and replaced with a new one after its end. When Calibration is marked, each of the five days are almost invariably isolated from the others by placing it between two of the seasons, metaphorically spreading out the burden of ill omens and weighty destiny through the year. It is considered foolhardy and unlucky in the extreme to tempt fate by placing all five days of Calibration together on a calendar, thereby disturbing the symmetry of the year.
Calendar Wheel design can be either excessively baroque, or rather minimalistic. Both styles are well-represented at all levels of society, both in the threshold and in the realm.
Calendar Wheels are frequently incorporated into Manse design in Creation, as all Manses inherently have some relationship with time and cyclic patterns.
In households on the Threshold, it is not uncommon to see temporary markers or even permanent design elements representing various days holy to the small gods (as part of the Small Gods Heresy). Dates important to the family are also so marked (birthdays and such), and both types of markers are often unlabelled, so this is circumstantial evidence of heresy at best.
The calendar used in the underworld is very similar to the Imperial Calendar, though the Stygian Calendar is not based on Lunar phases directly (since the moon of the underworld doesn't have them). Rather, it is tied to the Calendar of Setesh (a device), which in turn follows the yearly cycle in Creation. There are a few superficial changes:
The year numbering is different, as it doesn't use the Empress' Ascension as a starting point, but rather the start of the Calendar of Setesh. Realm Year 768 is 4910 on the Calendar of Setesh.
The Seasons of the Stygian Calendar are: Blood, Jade, Pyre, Bone, and Prayer.
The three phases of each season (equivalent to Ascending, Resplendent, and Descending) are: Inexorable, Indolent, and Ebbing. Thus, Resplendent Wood in Creation is the same as Indolent Jade in the Underworld.
The Stygian Calendar refers to Calibration as “Veneration”. It falls between Ebbing Bone and Inexorable Prayer, the same time as in Creation.
The denizens of the Underworld are just as interested in time and the cycle of the year as the Living, if for no other reason than the fact that these things are handy reminders of the past, and thus, the dead.
This is the Stygian Calendar