American dating format
However the 12 months of a year are of some obscure mystic origin and have no real purpose today except that people are used to having them (they do not even describe the current position of the moon).
In some applications, a date notation is preferred that uses only the year and the day of the year between 001 and 365 (366 in leap years).
A week starts with Monday (day 1) and ends with Sunday (day 7).
For example, the first week of the year 1997 lasts from 1996-12-30 to 1997-01-05 and can be written in standard notation as for applications like industrial planning where many things like shift rotations are organized per week and knowing the week number and the day of the week is more handy than knowing the day of the month.
Advantages of the ISO 8601 standard date notation compared to other commonly used variants: As dates will look a little bit strange anyway starting with 2000-01-01 (e.g.In addition, these formats have several important advantages for computer usage compared to other traditional date and time notations.The time notation described here is already the de-facto standard in almost all countries and the date notation is becoming increasingly popular.For example, the 53 weeks of the worst case year 1976 started with 1975-12-29 = 1976-W01-1 and ended with 1977-01-02 = 1976-W53-7.On the other hand, considering the lowest number of the last week of a year, the worst case is a non-leap year like 1999 that starts with a Friday, which ensures that the first three days of the year belong to the last week of the previous year.