Time zones - or what does your buddy's clock show?

[lorgerol]

Since Ryzom is an international game where you might meet people all over the world, it is important to know how they keep time, especially if you want to arrange times for meetings etc. This is a post about time zones, hopefully clearing up some common misconceptions. Daylight Saving Time often complicates matters, so there is an explanation of that as well.
The absolute reference time zone is UTC or Coordinated Universal Time, which is equivalent to GMT to all intents and purposes. Everything else is given relative to this. Here is a list of more common time zones:

UTC : Coordinated Universal Time, the reference for keeping time
European time zones:
GMT=UTC : Greenwhich Mean Time, the commonly used reference to specify time zones
CET=GMT+1 : Centreal European Time
BST=GMT+1 : British Summer Time
CEST=GMT+2: Central European Summer Time
American time zones:
PST=GMT-8 : Pacific Standard Time
CST=GMT-6 : Central Standard Time
EST=GMT-5 : Eastern Standard Time
PDT=GMT-7 : Pacific Daylight Time
CDT=GMT-5 : Central Daylight Time
EDT=GMT-4 : Eastern Daylight Time
Other examples:
Tokyo : GMT+9 all year around
Sydney : GMT+10 in summer / UTC+11 in winter (DST occurs in winter there)


Note that GMT does NOT change with Daylight Saving Time. At the time of posting, time zones in effect are BST in UK, CEST in most of Europe, and PDT/CDT/EDT in most of America.

Daylight Saving Time:
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This occurs during the summer in many countries and consists of switching clocks forward an hour sometime during April and switching them back sometime during October. Since this switching is done in America and Europe at almost the same time, to all intents and purposes the difference between what clocks show in Europe and USA stays constant. (Most of USA is -8/-6/-5 hours relative to England all year around). Note that some countries switch to DST during the winter, like Australia.

During the winter, the most common time zones used that you will meet are GMT and CET for Europeans and PST, CST and EST for Americans. During the summer, the time zones that SHOULD be used are BST and CEST, and PDT,CDT and EDT.

Common sources of confusion:
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Unfortunately people are sloppy. During the summer, people often use GMT to refer to the time in England (although the time in England is actually GMT+1) and use CET to refer to whatever the time is in the rest of Europe. Also, Americans love to use PST/PDT or EST/EDT etc. interchangeably during the summer to refer to the same thing, when they shouldn't. There are some counties in USA that actually do not switch to DST, so not differentiating between EST and EDT can be confusing.

I hope this little list will make you understand a bit better when your friend is having his breakfast. When specifying times for meetings, I recommend to everyone to either specify what time zone they mean, or use GMT as a reference.

[bobturke]

Bump. This is still useful.