Week Numbering
Weeks in a Gregorian calendar year can be numbered for each year. This style of numbering is commonly used (for example, by schools and businesses) in some European and Asian countries, but rare elsewhere.
ISO 8601 includes the ISO week date system, a numbering system for weeks – each week begins on a Monday and is associated with the year that contains that week's Thursday (so that if a year starts in a long weekend Friday–Sunday, week number one of the year will start after that). For example, week 1 of 2004 (2004W01) ran from Monday 29 December 2003 to Sunday, 4 January 2004, because its Thursday was 1 January 2004, whereas week 1 of 2005 (2005W01) ran from Monday 3 January 2005 to Sunday 9 January 2005, because its Thursday was 6 January 2005 and so the first Thursday of 2005. The highest week number in a year is either 52 or 53 (it was 53 in the year 2004). Schematically, this ISO convention translates as follows:
| Dates in January | Effect | |||||||
|---|---|---|---|---|---|---|---|---|
| M | T | W | T | F | S | S | Week number | Week assigned to |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 1 | New year |
| 1 | 2 | 3 | 4 | 5 | 6 | 1 | New year | |
| 1 | 2 | 3 | 4 | 5 | 1 | New year | ||
| 1 | 2 | 3 | 4 | 1 | New year | |||
| 1 | 2 | 3 | 53 | Previous year | ||||
| 1 | 2 | 53 or 52 | Previous year | |||||
| 1 | 52 | Previous year | ||||||
In some countries, though, the numbering system is different from the ISO standard. At least six numberings are in use:
| First day of week | First week of year contains | Weeks assigned twice | Used by/in | ||
|---|---|---|---|---|---|
| Monday | 4 January | 1st Thursday | 4–7 days of year | no | EU and most of other European countries and countries adhering to ISO 8601 |
| Saturday | 1 January | 1st Friday | 1–7 days of year | yes | Much of the Middle East |
| Sunday | 1 January | 1st Saturday | 1–7 days of year | yes | Canada, USA, Mexico |
Read more about this topic: Seven-day Week
Famous quotes containing the words week and/or numbering:
“Jesus would recommend you to pass the first day of the week rather otherwise than you pass it now, and to seek some other mode of bettering the morals of the community than by constraining each other to look grave on a Sunday, and to consider yourselves more virtuous in proportion to the idleness in which you pass one day in seven.”
—Frances Wright (1795–1852)
“The task he undertakes
Is numbering sands and drinking oceans dry.”
—William Shakespeare (1564–1616)