> Time zones are often represented by alphabetic abbreviations such as "EST", "WST", and "CST", but these are not part of the international time and date standard ISO 8601 and their use as sole designator for a time zone is discouraged.
> Such designations predate both ISO 8601 and the internet era; in an earlier era, they were sufficiently unambiguous for many practical uses within a national context (for example, in railway timetables and business correspondence), but their ambiguity explains their deprecation in the internet era, when communications more often cannot rely on implicit geographic context to supply part of the meaning.
Turns out PST and PDT are safe (no one else seems to use them) but something like CST is not: it could mean Central Standard Time (America/Chicago during standard time) or several other choices like China Standard Time (Asia/Shanghai).
> Time zones are often represented by alphabetic abbreviations such as "EST", "WST", and "CST", but these are not part of the international time and date standard ISO 8601 and their use as sole designator for a time zone is discouraged.
> Such designations predate both ISO 8601 and the internet era; in an earlier era, they were sufficiently unambiguous for many practical uses within a national context (for example, in railway timetables and business correspondence), but their ambiguity explains their deprecation in the internet era, when communications more often cannot rely on implicit geographic context to supply part of the meaning.
https://en.wikipedia.org/wiki/List_of_time_zone_abbreviation...
Turns out PST and PDT are safe (no one else seems to use them) but something like CST is not: it could mean Central Standard Time (America/Chicago during standard time) or several other choices like China Standard Time (Asia/Shanghai).
Ambiguity is bad.