ISO 8601

ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization (ISO) and was first published in 1988. The purpose of this standard is to provide an unambiguous and well-defined method of representing dates and times, so as to avoid misinterpretation of numeric representations of dates and times, particularly when data is transferred between countries with different conventions for writing numeric dates and times.

The standard organizes the data so the largest temporal term (the year) appears first in the data string and progresses to the smallest term (the second). It also provides for a standardized method of communicating time-based information across time zones by attaching an offset to Coordinated Universal Time (UTC).

Date and time
expressed according to ISO 8601:
Date 2012-11-23
Combined date and time in UTC: 2012-11-23T12:31Z
Date with week number: 2012-W47-5
Ordinal date: 2012-328

Read more about ISO 8601:  History, General Principles, Dates, Times, Combined Date and Time Representations, Durations, Time Intervals, Truncated Representations