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.
All of these alternatives can easily and automatically be distinguished from each other: The hyphens can be omitted if compactness of the representation is more important than human readability, for example as in In commercial and industrial applications (delivery times, production plans, etc.), especially in Europe, it is often required to refer to a week of a year.
Week 01 of a year is per definition the first week that has the Thursday in this year, which is equivalent to the week that contains the fourth day of January.
The date notation 2/4/5 has at least six reasonable interpretations (assuming that only the twentieth and twenty-first century are reasonable candidates in our life time).
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.
Especially authors of Web pages and software engineers who design user interfaces, file formats, and communication protocols should be familiar with ISO 8601.
Contents: Date, time of day, time zone, software hints.In this case, the Sunday of week 52 would be day number 3 52*7=367, i.e.only the last 367-365=2 days of the W52 reach into the next year and consequently, even a worst case year like 1999 has a week W52 including the days 1999-12-27 to 2000-01-02. Both day and year are useful units of structuring time, because the position of the sun on the sky, which influences our lives, is described by them.ISO 8601 should however be used to replace notations such as “2/4/95” and “9.30 p.m.”.Apart from the recommended primary standard notation YYYY-MM-DD, ISO 8601 also specifies a number of alternative formats for use in applications with special requirements.The international standard notation for the time of day is where hh is the number of complete hours that have passed since midnight (00-24), mm is the number of complete minutes that have passed since the start of the hour (00-59), and ss is the number of complete seconds since the start of the minute (00-60).