Perfect month
A perfect month or a rectangular month designates a month whose number of days is divisible by the number of days in a week and whose first day corresponds to the first day of the week.[1][2] This causes the arrangement of the days of the month to resemble a rectangle. In the Gregorian calendar, this arrangement can only occur for the month of February.
Constraints
[edit]To satisfy such an arrangement in the Gregorian calendar, the number of days in the month must be divisible by seven. Only the month of February of a common year can meet this constraint as the month has 28 days, a multiple of 7.[3]
For a February to be a perfect month, the month must start on the first day of the week (usually considered to be Sunday or Monday). For Sunday-first calendars, this means that the year must start on a Thursday, and for Monday-first calendars, the year must start on a Friday. It must also occur in a common year, as the phenomenon does not occur when February has 29 days.
Occurrence
[edit]In the Gregorian calendar, the phenomenon occurs every six years or eleven years following a 6-11-11, 11-6-11, or an 11-11-6 sequence until the end of the 21st century. The most recent perfect months were February 2015 (Sunday-first) and February 2021 (Monday-first).[4] Due to calculation rules, the years 1700, 1800, and 1900 are not leap years, causing a shift in the sequence with a spacing of twelve years between 1698 and 1710, 1795 and 1807, and 1897 and 1909 respectively; however 2094, 2100 and 2106 will all feature perfect months with spacings of six years on Monday-first calendars.
The next perfect months will be February 2026 (Sunday-first) and February 2027 (Monday-first).
Attributes
[edit]The calendar arrangement brings together notions of harmony and organization.[5][6]
See also
[edit]References
[edit]- ^ Norris, Phil (1 February 2021). "February is looking to be a perfect month on paper". GloucestershireLive. Retrieved 1 February 2021.
- ^ de La Taille, François (31 January 2021). ""Mois parfait", palindrome: quand février 2021 rend fous les fétichistes des chiffres". BFMTV.com (in French). Retrieved 1 February 2021.
- ^ Shaloo Tiwari (1 February 2021). "Why Is February 2021, a Rectangle Month? Happy Posts Take Over Twitter as the Second Month This Year Forms a Perfect Rectangle Shape!". latestly.com. Retrieved 1 February 2021.
- ^ Lombart, Gaël (30 January 2021). "Février 2021, mois «parfait»... sur le calendrier". leparisien.fr (in French). Retrieved 1 February 2021.
- ^ Focraud, Arnaud (29 January 2021). "En février, vous entrerez dans un "mois parfait" (selon le calendrier)". lejdd.fr (in French). Retrieved 1 February 2021.
- ^ Leray, Olivia (1 February 2021). "On ne pouvait pas le rater. Malgré le coronavirus, février sera parfait". francetvinfo.fr (in French). Retrieved 1 February 2021.