One day on Avalon equals about 127.7 hours on Earth. That’s a lot of time and Avali don’t just split that into hours and minutes, but into periods, then hours and minutes and so on. Avali sleep multiple times per day, 6 times on average, so this is how many periods there are. As in: sleep cycle periods.

6 periods make up one day and each of those is split into 36 hours, is split into 36 minutes, is split into 36 seconds. The number of divisions may also seem odd, but they make perfect sense when viewed in base-6, where 36 is "100".

This also means that the word "second" here does not mean seconds as you’re used to, its length defined by a different arbitrary subdivision of a different length of "one day" compared to Earth. One "second" on an Avali’s clock ticks by in a time that a human clock would record as 1.64 of its seconds.

Avalon orbits Valaya. Valaya orbits Solakku. So it is the length of Valaya’s orbit that determines the length of one year here: one round trip around the star, just as the humans do it. Its quite long, too, a little over 13 years on an Earth calendar. Even with Avalon’s long days, that leaves 893 days to be organized.

The primary subdivision is seasons, of which there are 20. By default, they are 45 days long, but 45 times 20 is too many days. So, 7 seasons have one day removed and are only 44 days long. Unlike Earth calendars, though, these short and long seasons are not interspersed. The Avalonian year starts with the 7 short seasons, all back to back, before going with the full 45-day ones for the rest of the year.

However, even this is not perfect. A small error builds up in the counting of days with every orbit of Valaya, which eventually leads to a correction similar to a leap year. These occur every 180 years and don’t add a day, but remove one. The 8th season, usually the first with 45 days, skips its last day and becomes an additional short season of only 44 days. These leap years are incredibly rare (once every ~2,340 Earth years) and are usually celebrated. The next one will be the year 540 (in over 250 Earth years).

There is a second subdivision that was grandfathered in from old calendars based on the movements of Valaya’s other moons: a set of 12 days forms one "cycle". However, this is considered a separate system and almost never lines up with the rhythm of seasons in the calendar. They are like weeks are to days and months on human calendars.