You might have noticed that the date format used everywhere on this website is in the year-month-day format. Look, it’s right there at the bottom of this page! This is a highly intentional and conscious choice.
Date formats are notoriously ambiguous, especially between month-day-year, and day-month-year. ISO 8601 is as unambiguous as it could be, as the first field is clearly a four digit year, and the next two fields are never used the opposite way around, and simply descend in the unit’s overall length.
ISO is an NGO with membership from 165 nations in charge of standardizing everything from preparing a cup of tea to social responsibility. This particular date format is standardized in ISO 8601. Unlike other date formats, ISO 8601 provides a standardized method of using it. This standardization extends to all aspects of using the format and storing time data, including dates, times, time zones, time intervals, and arithmetic with dates. This is unlike Unix time which is a great, simple solution for storing time, however is not human-readable, and cannot store time zones, and other time information.
The Internet Society has chosen ISO 8601 as its recommendation as the date format for use on the internet in RFC 3339, further propagating the standard in the digital environment.
Because of this standardization, using the ISO 8601 format, especially in an automated environment, is highly predictable and reproducible.
ISO 8601 is humanity’s opportunity out of the confusion of day-month-year and month-day-year. We can seize this moment, and proceed down a path of time-telling enlightenment, or stumble back into our darkest days of continuously sending clarifying emails, and showing up on the wrong day. So, for the good of all human kind, use ISO 8601.