Anyway you slice it, it’s 90 + 1 days – (dec 22 – mar 21)
Two things. First, the quarter of the year is a great bit of design (not mine, btw). Each quarter is either 13 seven-Day weeks, or it’s seven 13-Day somethings (no name yet for this period of time. The Spanish called them “trecena”, Mesoamericans likely have their names for them.)
At any rate, it’s the period (91 days) where the Weeks and 13-day periods come together. Also a great many market weeks.
Once it was discovered that theAbysmal Year divides into even 91-day Quarters, and excepting one day each quarter, the day midway between its beginning and end, thus midway between the Southern Solstice and the Northward Equinox. That creates eighths of 45 days excepting the mid-Quarter day.
For Year 3 Quarter 0, the mid-Quarter day falls on Lunation 1 Day 26; it always falls on Month 1 Day 17, House 0 Day 45, Quarter 0 Day 45, Year 0 Day 45 (feb 5).
This provides us with the spokes for a Wheel of the Year. Each Quarter begins and ends on or about the Solstices and Equinoxes, beginning with the Southern Solstice (Winter Solstice in the Northern Hemisphere, Summer in the Southern). Here we begin with the Southern Solstice, and in these northern latitudes, the day by day, we see more and more sunlight for longer and longer. This rate of change from day to day manages to go from about a minute more of sunlight from one day to the next just after the New Year, to seven or eight minutes from one day to the next. In the Arctic and Antarctic regions, it must be a dramatic change across the course of this Quarter.
Please keep in mind (or don’t, it’s your mind) that the Quarter are approximate and don’t always fall on the Solstices (and rarely on the Equinoxes). The approximation better aligns us with the changes in sunlight and seasons. Scheduling by quarters with these changes in mind might be a way of better distributing annual responsibilities, events, celebrations.