Leap week calendars

The Symmetry454 calendar (Sym454) is a proposal for calendar reform created in early 2004 by Dr. Irv Bromberg, an assistant professor at the University of Toronto, Canada (retired in 2018). It is a perennial solar calendar that conserves the traditional month pattern and 7-day week, has symmetrical equal quarters, and starts every month on Monday.

leap week calendar system in which weeks start on a Monday and the first week of a year starts from the Monday closest to 1 January; e.g. Thu. 31 Dec. 2009 is 2009–W53–4

proposal for calendar reform

proposal calendar having 13 months per year and a leap week