FW: Time Zone Database

Markus Kuhn Markus.Kuhn at cl.cam.ac.uk
Thu Apr 9 08:37:03 UTC 1998

Clarissa Gammelt wrote on 1998-04-07:
> How often are there changes to the time difference information
> (approximately)?

A couple of times per year, whenever Arthur David Olson has time, received
patches, or feels that it is necessary.

> Who provides that information?

There are many sources, including the International Air Transport Association
<http://www.iata.org/>, international phone operators, media reports,
specialized books, and many personal investigations of the tz mailing
list members.

> When in general are the dates for those changes? Are they regular, or 
> each year different? Are there any rules?

No rules, because the politicians who mess around with time zone legislation
also follow no rules.

> Which countries do or don't have summer or winter time?

Changes every year. Check the data base.


Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK
email: mkuhn at acm.org,  home page: <http://www.cl.cam.ac.uk/~mgk25/>

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