The current year as of Galebound's first book is 1120 AV—Anno Ventus, years since the inception of the Gale (in its current incarnation).
The Dusk uses nonary for most counting, including timekeeping. More info on nonary (base-9) here. Numbers on this page are written first in decimal (base 10) and then in nonary.
Dusk has a twenty-seven hour day (30 in nonary), traditionally divided into thirds: nine hours of morning, nine hours of midday, and nine hours of evening evening (10 each in nonary). As the world is tidally-locked, denizens of the Dusk never see a true night. However, there is a daily eclipse which signals the start of a new day. The period of the eclipse, known as the Dark Hour, takes up the first hour of the morning.
The Dark Hour eclipse is not caused by a moon (this planet has no moon), but by the transit of the much-larger second planet in the star system.
Astronomically speaking, the day is as long as a year, but this makes for unwieldy timekeeping. The year is divided into 243 days (300) and nine cycles (10). The concept of a "year" originated in Iridesa, codified by the Saint Anges in the year 346AV. Years are based (loosely) on the gestational period of a human as it was understood in Anges's time and cycles are based on the average menstruation cycle.
All months are 27 days. There are three weeks in a month and nine days to a week.
As all cycles have the same number of days, this calendar format applies to them all. The 23rd day of a month will always fall on Tredin.
A timeline of events mentioned or at least strongly referenced in canon.
Not everything has an exact date, but if more than one thing happened in a year/cycle/day it’s more-or-less listed chronologically.