The calendar is based on a 28-29 day moon cycle numbered by observation, and also using clues like the solstices and the equinoxes to divide the years into three types, Long Winters, Long Summers, and Short Years. In a 38 year cycle there are 21 Long Summers, 10 Long Winters, and 7 Short Years.

The year starts on the first new moon after the Spring Equinox. Long Summers and Long Winter years have 13 moon cycles, and last 370-371 days. The Short Years have 12 Moons, and last exactly 342 days.

Typically the moons are broken into four 7 day sections, the new Moon, the waxing Moon, the Full Moon, and the waning moon. Any extra days for the next new Moon are tacked onto the end as extra outwith the usual weekday naming conventions.

Each of the moons has a name, based on the more common activities in most years when it appears.