Time Zone

Attempt at global Standard Time.

Can drive your Culture - see Eastern Standard Tribe.

Map showing where timezone-time is surprisingly far from solar time. China is about as big across as the continental United States and has only one huge time zone.

Handy tool/site for lining up: http://www.worldtimebuddy.com/

On User Options, enter a time zone to localize page modification times. See Zope's Date Time.py for allowed formats.

Note that Time Zone-s don't follow borders

• in the US, a number of states are split across Time Zone-s
• many other countries are split across Time Zone-s also

DST is a nightmare: see http://www.webexhibits.org/daylightsaving/index.html

• UTC is the Coordinated Universal Time, which does not move for Daylight Savings Time (DST).
• GMT does move, though when moved it's not actually called GMT, but rather BST (British Summer Time).
• Some parts of the US (e.g. Arizona, Hawaii) don't do DST.
• Of those parts of the US that do DST, they don't switch on the same date as the GMT/BST switch.

Most LinuxOS apps (e.g. Postgresql Timezone Problem) will give you functions to convert a timestamp, given an Olson Time Zone value.

• Oct'2009: interesting Jon Udell look at some historical info
• for US-only situations, there are still only a relatively small number of values you need to support (although the full reference db includes many redundant values).
• but for outside the US, you need to include a huge number of values.
• http://www.twinsun.com/tz/tz-link.htm
• http://en.wikipedia.org/wiki/Zoneinfo
• http://en.wikipedia.org/wiki/List_of_zoneinfo_timezones