Yerm
| Epoch | Confidence |
|---|---|
| 19 May 622 CE +12:00:00 | Exact |
Overview
The Yerm calendar, short for Year Moon, is a calculated lunar calendar proposed by Karl Palmen in 1998.
It features lunar months of alternating 29 or 30 nights organized into "year moons" of 17 or 15 months. The first and last month of each yerm is 30 nights. Yerms follow a repeating pattern of 17-17-15 months, with an extra 17-month yerm added after the 17th pass of this pattern, for a total of 52 yerms in a cycle.
Rather than using days, this calendar uses nights which begin at local noon. Cycle 21 began on 11 November 1996 CE at noon.
Months begin at or around the New Moon and are broken into weeks of 7 nights that correspond to the lunar phases. The fifth week is either one or two nights long, consisting of "Fifth Moonnight" and sometimes "Lastnight", to keep the week aligned to the phases. Weeknights are prefixed with the week number of the current month followed by the name of the night.
Info
| Months per yerm | Nights per yerm |
|---|---|
| 17 | 502 |
| 15 | 443 |
| # | Weekday |
|---|---|
| 1 | Moonnight |
| 2 | Tuesnight |
| 3 | Wensnight |
| 4 | Thursnight |
| 5 | Frinight |
| 6 | Saturnight |
| 7 | Soonnight |
| 30th Night | Lastnight |
Accuracy
This calendar is a simple cyclical equation with a known epoch and is thus exactly accurate.