The northern nations of Cavnal, Tulay, Istia, Ceruvay, Meritac and Cromis all use a standard calendar developed eight centuries ago by an Istian Godar named Tarvar. The year is reckoned from the commonly accepted year of Istia's founding, which some of the other nations have protested—unsuccessfully—in the eight hundred years since the calendar's adoption.
The year is divided into four seasons, with a week-long festival, or thelia, marking the beginning of each season. Every season has four months ranging between 20-22 days, giving a 16-month calendar with four unreckoned weeks, one at the beginning of each season.
The year begins in Athen, the winter season, which starts with the week leading up to the winter solstice, called Kalethelia. The solstice itself is not the beginning of the year, but seven days prior. In Earth terms, this would correspond roughly to the week leading up to December 22.
The four months of Athen are Turathen, Galathen, Vorathen, and Kaerathen.
Kalethelia is the principle festival of the year in Cavnal. The last day of Kalethelia is celebrated with the Crown Ball in Brinmark. Every city in Cavnal holds a public celebration the same night, featuring dancing, music, magicians (typically mages who have to put on cheap magic shows to earn enough coin to keep themselves fed), and food. In the country, the festival is typically celebrated privately, with the traditional fare of honeyed cakes and dark ale consumed in vast quantities. The entire week of Kalethelia, garlands of purple and gold decorate the houses and city streets of Cavnal.
Kalethelia is not as widely celebrated in other nations. In Istia there is no festival at all. Rather, Kalethelia is a week steeped in superstition and folklore. On the last night of Kalethelia, it is common for Istians to shutter their windows and barricade their doors, and spend the evening reciting stories from memory.
The spring season is called Ras, and begins with the celebration of Avothelia, the week leading up to the spring equinox. In Earth terms this season lasts roughly from mid-March to mid-June.
The four months of Ras are Konseras, Seras, Oberas, and Danseras.
Avothelia is the primary festival in Istia, which marks the end of the brutally cold winter season and marks — in some more northern regions — the return of the sun. Istians do not typically extend the festival the entire week, but on the last day, the date of the spring equinox, most Istians will spend the entire day outside, eating, playing music, acting out dramas, and performing extensive religious rituals. The celebration ends well after midnight, and no work is expected to be done the following day.
In Cavnal, the festival is much more subdued. Green and silver are the colors of Avothelia, and celebrations are much more common in the country villages and towns than in the large cities. In contrast to Istia, there is no religious element to Avothelia in Cavnal. The more important spring festival is the Medemy Fair, which is a remnant of the old annual trade fairs.
The third season of the year is called Verren, and begins with the week leading up to the summer solstice, or Terethelia. In Earth terms this would extend from mid-June to mid-September.
The four months of Verren are Anverren, Teverren, Ereverren, and Paruverren.
Terethelia is the predominant festival in Cromis and Meritac. In Cavnal, many members of the nobility leave Brinmark during this week and vacation along the southern coast. In Istia, Terethelia is associated with the return of the migrating whales and other fish. This is typically the day that new Istian ships make their maiden voyage, since it is viewed as a day favored by the divine. Blue and copper are the colors associated with this festival.
The last season of the year is Marras. It begins with the week leading up to the autumnal equinox, called Parethelia. In Earth terms it would last roughly from mid-September to mid-December.
The four months are Venemarras, Oremarras, Marras, and Kaermarras. The third month was formerly called Imarras but over time it was reduced simply to Marras.
Parethelia is commonly considered the "harvest festival." In Istia, where agriculture is far less important, Parethelia is mostly ignored, but in the more rural areas of Cavnal it is the predominant festival of the year. The week leading up to the autumnal equinox is typically spent with a vast community effort at bringing in the harvest — especially in northern regions where the growing season is shorter and impending frosts threaten the crop. Red and brass are the colors of Parethelia.