What is a time zone?

John Cowan cowan at mercury.ccil.org
Mon Feb 12 00:19:21 UTC 2001

Gwillim Law scripsit:

> If
> anyone is not satisfied with ISO 8601, they must want to convey more
> information than just the offset from UTC.  What useful information is
> imparted by EST (or CDT), that isn't imparted by -05:00?

In particular, if we are going to talk about future times (including
recurring times), we really need to represent the entire tz name.
For example, my employer is currently publishing news articles at
1705 EST and others at 2000 EST.  But we do not state our publication
dates in EST, nor in GMT, but in "New York time", because we will
always be publishing relative to America/New_York, no matter how
much that changes.  Currently, New York time is -05:00, but it regularly
changes to -04:00 in (boreal) summer, and in principle it could
change to some other offset altogether.

John Cowan                                   cowan at ccil.org
One art/there is/no less/no more/All things/to do/with sparks/galore
	--Douglas Hofstadter

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