Although a number of means exist for marking the days and the passage of time during a year, nearly all folk in Faerun have adopted the Calendar of Harptos. Even the cultures and races that don’t favor this method of marking time are aware of it, with the result that it is recognized across nearly all races, languages, and cultures.
A year on Toril consists of 365 days.
In the Calendar of Harptos, the year is divided into twelve months of thirty days, loosely following the synodic cycle of Selune, the moon.
A month is made up of three ten-days, also known as rides.
Five annual holidays, falling between the months, complete the 365-day calendar.
Once every four years, the Calendar of Harptos includes Shieldmeet as a “leap day” following Midsummer.
Individual days of a tenday have no special names. Instead, they are denoted by counting from the beginning of the period (“first day,” “second day,” and so on). Days of the month are designated by a number and the month name. For example, sages would record an event as occurring on “1 Mirtul” or “27 Uktar.” People might also refer to a given day by its relationship to the current date (“two tendays from today”) or the nearest holiday (“three days past Greengrass”).