Last night, Sunday 2015-11-01 at 2AM, you should have moved your wall clocks, alarm clocks, watches and appliance clocks back one hour to 1AM. In the strange world of DST, the clock sweeps between 1 and 2AM twice.
By putting forward the hands of the clock you shall not advance the hour.
~ Victor Hugo (born:1802-02-26 died:1885-05-22 at age:83)
Sometimes called DST (Daylight Saving Time), summer time or war time. The British call it BST (British Summer Time), BST. The French call it heure d'été. The Germans call it Sommerzeit. The Dutch call it Zomertijd.
It is a scheme to get people to wake up earlier and go to bed earlier to save electricity. You set clocks ahead a hour (or more) in spring and set them back in the fall. Commonly, you set the clock an hour forward at 2:00 A.M. on the second Sunday in March) and set it back one hour at 2:00 A.M. on the first Sunday in November. You can remember with the mnemonic spring forward, fall back.
DST globally is not as simple as in North America. The rules vary over time and by jurisdiction.
In British Columbia, Canada, where I live, local time is UTC (Coordinated Universal Time/Temps Universel Coordonné) minus 8 hours for PST (Pacific Standard Time) and UTC minus 7 hours for PDT (Pacific Daylight Time). DST starts on the second Sunday in March and ends the second Sunday in November.
Newfoundland is odd in that it in not an even hour difference from GMT/UTC. Newfoundland Standard Time is UTC minus 3.5 hours. It also odd in that they do the DST flip at 00:01 AM rather that 02:00 AM like the rest of Canada.
DST causes all kinds of headaches for computer programmers:
Windows Vista, W2008, W7-32, W7-64, W8-32 and W8-64 is supposed to automatically keep your clock in sync with a Microsoft time server, but for me it does not work. I suspect the problem is it is overloaded. I got it to work by configuring a non-Microsoft pool timeserver.
Linux automatically probes time servers with NTP (Network Time Protocol) to keeps its clock in sync.
Someday, computers will have built-in GPS (Global Positioning System) units and they will be able to configure the local time zone automatically. But for now, you must do that manually in the control panel.
However, other people hated the order and deliberately screwed it up by inventing DST, with every jurisdiction deciding for itself on just how much DST to have. We are working our way back slowly but surely to the old system, that does not even have the uniformity of solar synching.
The Internet is shrinking the world further. To get ahead of the curve, perhaps we should set our watches to UTC, or at least the alternate time function, such as I have on my radio-synched desk clock.
You’d think, at least in airports, clocks would also display UTC as would flight schedules. Once people got used to this, they would not be confused by changing time zones as they moved west or east between zones. The lengths of flights would be clearer. Tracking tummy time would be easier.
It would be a Good Thing™ at least if there were a U.N. department of time that maintained the official list of time zones and their DST rules. It is a difficult job. It should not be duplicated.
To get an idea what a nightmare DST has created have a look at Oracle’s table of DST changes. The list is so huge, it can never be accurate.
To make sense of time every computer program needs a giant database that not only tracks what every micro jurisdiction is doing to meddle with time, but all they have ever done. This is ridiculous.
In most of Canada, DST begins and ends at 2 AM on the same days as the USA. However, in Newfoundland and Labrador, DST begins one minute after midnight local time on the second Sunday in March. On the first Sunday in November time returns to standard at one minute after midnight local time.
A few areas of Canada don’t use DST at all including Fort St. John, Charlie Lake, Taylor, Dawson Creek and Creston in British Columbia and most of Saskatchewan (except Denare Beach and Creighton).
|Daylight Savings Change Dates in the USA and Canada|
|year||DST starts||DST ends|
|2008||March 9||November 2|
|2009||March 8||November 1|
|2010||March 14||November 7|
|2011||March 13||November 6|
|2012||March 11||November 4|
|2013||March 10||November 3|
|2014||March 9||November 2|
|2015||March 8||November 1|
|2016||March 13||November 6|
|2017||March 12||November 5|
|2018||March 11||November 4|
|2019||March 10||November 3|
|2020||March 8||November 1|
Other countries use different dates or don’t use DST at all. They may use the same time zone, but have different DST rules. That’s why you don’t configure your time zone directly in the OS, but rather chose a city with representative DST rules.
Arthur David Olson dedicated his life to maintaining a database about timezones and DST. Individual cities change their minds annually about the begin and end date/times for DST. The boundaries of the world’s timezones are constantly being tweaked. Every international computer program in the world has to incorporate all this historical lore to function properly. Paul Eggert is the new editor and maintainer of the tz database. Oracle updates Java with the new information with each release of the JDK (Java Development Kit)/JRE (Java Runtime Environment). If you use an old JDK/ JRE, you will get out-of-date timezone/DST information. He had some legal trouble with an astrology company that claimed ownership of such data. Happily, Oslon prevailed in the legal challenge. New versions of Java incorporate the latest timezone trivia information. Oracle also releases timezone updates for older versions.
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