For those who've read Not Gods But Monsters, you may notice a strange series of words at the beginning of each that looks suspiciously like a date. That's because it is (shocker, I know). Much like the development of the Byraelian language, the creation of the calendar was intended to point to the world's more unique qualities.
Instead of the standard 12-month, 7-day week of the Gregorian calendar, the Byraelian calendar is composed of 355 days broken up into 10 months. These are likewise broken down into four seasons: Early, Midsummer, Harvest and Late. While one might think that it would break down to 35 days each, the days are actually not distributed evenly because of the four season cycle. There are only two months in both the Midsummer and Late seasons, and as such each are longer by number of days.
Because there is no "seven days of creation" in the Byraelian dogma, there are no weeks in a month. To go in-hand with this, there are also no days of the week (Monday, Tuesday, etc.). Days are referenced by the number (example: The Fourth of Iefimond).
Note: The sample calendar below only has days broken up into 5-day segments for the convenience of display. Without the notion of weeks, its just as likely that true Byraelian calendars would be displayed as unbroken rows of days, separated by month. Whether shown in vertical or horizontal format is likely dependent on a regional basis (or even by the religious sect).