The standard Fronterran calendar is based on the movement of celestial bodies within the solar system. Each month of 31 days represents the orbital period for Fronterra to complete 1 orbit around Wilderos. Each year contains 12 of these months and coincides with the period for Wilderos to orbit the sun. These dates are very very close to matching but not quite perfect, and every half century the Cosmological Calendar Commission of United Astrographers convenes to adjust the calendar to fit the planet's relative location within the solar system, sometimes adding or subtracting a day or two from the current date.
The weekdays on Fronterra do not hold any astrological significance and are merely a holdover from the commonfolk, who use it for day to day communication. The names of the days are named after the major known heavenly bodies within the solar system. These weeks perfectly align with the yearly dates so each year has precisely 62 weeks.