ISO 8601
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Overview
ISO 8601 is a standard aimed at providing unambiguous date and time-related data representation. The standard applies to representations of dates in the Gregorian calendar, of times based on 24-hour timekeeping system, with an optional UTC offset.
Dates and times are arranged so the largest temporal term is placed to the left, and each successively smaller term is placed to the right of the previous term. The following units are represented: year, month (or week), day, hour, minute, second and fraction of a second. The representation is written as a combination of digits and special characters ("-", ".", "T", "W" and "Z"). Full words such as "January" or "Thursday" are not allowed in ISO 8601 interchange representations. Each date and time has a fixed number of digits, with a leading zero padding.
There are two format: 1. Basic format, with a minimal number of separators. The basic format should be avoided in plain text. 2. Extended format with separators added to enhance human readability.
Separators:
- "-" (hyphen) is used to separate date values (year, moth, week and day).
- ":" (colon) is used to separate time values (hours, minutes and seconds).
Values may be dropped from any of the date and time representations, but only in the order from the least to the most significant. "2018-11" is a valid ISO 8601 date.