Cal7 is a proposed leap week calendar that heavily relies on the number seven. A week has, as usual, 7 days, but also a month has 7 weeks and a year has 7 months. The only deviation are odd-numbered months, which have 8 weeks, except for the last one where the eighth week is the leap week. A leap week occurs every 7th year and every 29th year (the rest of the leap rule is yet to be defined). Cal7 can thus be considered a loose solar calendar.
The ISO 8601-like date format is
±CCYY-M-W-D. If not specified otherwise, Cal7 agrees with this international standard, e.g. that Monday is the first day of the week.
In the table, an asterisk * denotes months that always include Holiweek and a dagger † shows the month that is 8 weeks long only in leap years.
The following table compares Cal7 with similar proposals, assuming weeks start on Monday in all cases. The academic terms listed are synchronized with Cal7 months; they could be aligned with other months instead.
|Octalendar||month 1||month 2||month 3||month 4||month 5||month 6||month 7||month 8†|
|Academic (example)||Spring semester||Summer break||Fall semester|
|Winter semester||Summer semester||Summer break||Winter semester|
|Epiphany/Hilary trimester||Trinity trimester with summer break||Michaelmas trimester|
The Christian holidays are fixed as follows: Carnival, Easter and Pentecost are at month boundaries, 7 weeks apart. Christmas Eve is one week before New Year’s Eve unless there’s a leap week and Lady Day is 40 weeks before Christmas (not 9 months).
Note that Halloween is on -6-6-6, a Saturday. Most holidays are conveniently placed onto Sundays, unless they are already associated with a fixed day of the week.
|New Year||-1-1-1||the first day of Monmonth|
|Circumcision of Christ||-1-1-1||the first day of Monmonth|
|Epiphany||-1-1-7||was 6 Jan or Sunday close by, also Theophany|
|Candlemas||-1-4-7||was 2 Feb or Sunday close to it, Presentation of Jesus at the Temple|
|Valentine’s Day||-1-6-7||was 14 Feb|
|Shrove Monday||-2-1-1||the first day of Tuesmonth, 7 weeks before Easter||Carnival|
|Women’s Day||-2-2-7||was 8 Mar|
|Lady Day||-2-3-7||was 25 Mar, Feast of the Annunciation of the Blessed Virgin|
|Easter Sunday||-2-7-7||the last day of Tuesmonth (a week later than proposed for Sym454)|
|Easter Monday||-3-1-1||the first day of Wednesmonth|
|Labor Day||-3-3-3||-3-3-1? -3-7-5?, Workers’ Day was 1 May (or 1st Mon in Sep in NA)|
|Mother’s Day||-3-3-7||was 2nd Sun in May etc.pp.|
|Father’s Day||-3-4-7||was 3rd Sun in Jun etc.pp.|
|Ascension||-3-7-4||40 days after Easter||Pentecost|
|Pentecost Sunday||-3-8-7||the last day of Wednesmonth, 7 weeks after Easter|
|Pentecost Monday||-4-1-1||the first day of Thursmonth, Our Lady of Holy Church|
|Corpus Christi||-4-2-4||60 days after Easter|
|Midsummer||-4-2-7||was ca. 21 Jun|
|Feast of the Transfiguration||-4-7-7||the last day of Thursmonth, was 6 Aug|
|Feast of the Cross||-5-8-7||the last day of Frimonth, was 14 Sep|
|Michaelmas||-6-1-7||was 29 Sep, Feast of the Archangels|
|Halloween||-6-6-6||a Saturday, was 31 Oct, Samhain||All Hallows|
|All Hallows||-6-6-7||was 1 Nov|
|All Saints||-6-7-7||the last day of Saturmonth|
|Thanksgiving||-7-1-7||Harvest feast, was 4th Thu in Nov, 2nd Mon in Oct, 1st Sun in Oct etc.pp.|
|1st Advent Sunday||-7-2-7||Advent|
|St. Nicklas||-7-3-6||was 6 Dec|
|2nd Advent Sunday||-7-3-7|
|3rd Advent Sunday||-7-4-7|
|4th Advent Sunday||-7-5-7|
|Christmas Day||-7-6-7||was 25 Dec|
|Boxing Day||-7-7-1||was 26 Dec|
|New Year’s Eve||-7-7/8-7||depends on leap week|