The worlds of Jaern and Cahyali have similar calendars, but their seasons and holidays tend to differ. Jaern, being a mostly tropical planet with vast oceans, has a notably different global climate than Cahyali, which is more temperate. The days of the week and months are the same, however.

Weeks have six days, and months have thirty days each. A year is exactly ten months, or 300 days.

Jaern has three seasons, although none become particularly cold except in polar regions.

• Akvofojo: The rainy season and the planting season. The coldest of all Jaern's seasons, often overcast even on days when it doesn't rain. Jaernians associate Akvofojo with rebirth, life, and new beginnings.
• Fajrofojo: The hot season and the growing season. Temperatures can soar during this season, and fires become common in more inland areas. Jaernians associate Fajrofojo with the sun, discovery, and relaxation- most educational institutes grant their students a major break in mid-Fajrofojo, for about half the month of Led. Fajrofojo is significantly shorter than the other months, and is considered a sort of transition period between Akvofojo and Sekafojo.
• Sekafojo: The dry season and the harvest season. During this time, temperatures fall and deciduous trees can begin to lose their leaves. The end of Sekafojo, after harvest, is considered a time when evil spirits and demons can be let into the world. Jaernians associate Sekafojo with change, endings, and abundance.

Most of Jaern's holidays are guided by priesthoods of gods. Religious life and holiday is very intermixed in Jaernian culture, with the populace going from temple to temple to pay their respects during major holidays.

The leap year of Jaern. Every ten years, a three day holiday is added to the end of the year (Pim 31, 32, and 33) to adjust the calendar by the fractional days which have accumulated. Being born during this holiday is considered very lucky. Many Jaernians do not work during this holiday.

The Festival of the Foretelling is significant to At'enites, who meditate on the first day, seeking inspiration and guidance from their goddess. On the second day, this vigil ends and temples hold large feasts, and at the end of these feasts a temple's high priest comes out to preach and divine future events for the populace. On the third day, the festival winds down as At'enites spend time with their loved ones and celebrate life.

Celebrated by Isisites, this day commemorates when Isis returned to Jaern in 10048 and cured the lands of a plague that had been ravishing it. The Day of Rebirth is a rather toned-down holiday, with many celebrating quietly at home and perhaps visiting a local temple of Isis to pay respects.

This holiday is marked on the calendar but not commonly celebrated outside of Ra'ite circles. It marks the nearest approach of Onra, the sun, and the shortest day on Jaern. Ra'ites are solemn during this day, working carefully in their temples to prepare for any calamities that may occur. According to superstition, dark forces can enter the world on the shortest day, and many circles of evil gather their forces.

A celebration of all that is living. Food, singing, dancing, and storytelling occur throughout Isisite sanctuaries. Patients are brought down to the worship areas if they are able, entertainers are retained, and every caterer in town is employed. Games and competitions are held for groups and individuals, and prizes awarded.

This holiday is marked on the calendar but not commonly celebrated outside of Ra'ite circles. It marks the farthest approach of Onra, the sun, and the longest day on Jaern. Ra'ites open their temples and celebrate on this day, marking the occasion with food, wine, and complex dances meant to imitate the movement of heavenly bodies and pay respect to Ra.

During this holiday, priests of Osiris observe a Jaern Week. They speak in public about the wonders of nature. They explain why it is important, why people need to depend on nature, and what they can do to preserve it. They teach those who are willing what they can do to preserve the wild, giving respect to Osiris in the process. It is considered a good omen to host a priest during this time, and some noble families vie for the honor.