The Celtic Tree Calendar has 13 moons, each ruled by a different tree.
Moons:
Followed by a day not ruled by any tree for it is the "day" of the proverbial "year and a day" in the earliest courts of law. This day is the day following the Winter Solstice.
I artificially created the leap-day by giving a 29th day to Luis, for ease of use, but have no information to confirm when or if a leap-day is calculated.
Although called moons, this is a solar, not a lunar calendar.
I've cross-referenced this calendar in my perpetual calendar with several other solar calendars.