Thursday, January 18, 2007

2007 USA and Canada clocks confusion

Daylight time: Springing ahead and falling back

Last Updated October 27, 2006

Daylight time was first enacted in Germany in 1915, quickly followed by Britain and much of Europe and Canada.

Because the sun shone for a time while most people were asleep, it was reasoned that light could be better used during the day. The solution was to push the clocks ahead one hour in springtime, forcing people to wake an hour earlier. They would therefore expend less energy trying to light their homes, for instance, if time were adjusted to suit their daily patterns.

When the days started getting shorter in the fall and people awoke to increasing darkness, the clocks were turned back an hour to get more light in the morning.


Although first instituted in 1915, the idea of daylight time had been batted around for more than a century. Benjamin Franklin suggested the idea more than once in the 1770s while he was a minister to France. But it wasn't until more than a century later that the idea of daylight time was taken seriously.

William Willett, an English writer revived the idea in 1907, and eight years later Germany was the first nation to adopt daylight time. The reason: energy conservation. Britain quickly followed suit and instituted British Summer Time in 1916.

Several areas, including parts of Europe, Canada and the U.S., followed suit during the First World War. In most cases daylight time ended with the armistice.

During the Second World War, a different form of daylight time was reinstated by Britain and clocks were set two hours ahead of GMT during the summer. It was known as Double Summer Time. The time shift didn't end with the summer, as clocks were rolled back to be one hour ahead of GMT through the winter.

The Uniform Time Act, enacted by the U.S. Congress in 1966, established a system of uniform (within each time zone) daylight time throughout most of the U.S. and its possessions, exempting only those states in which the legislatures voted to keep the entire state on standard time.

Canada and abroad

It's up to each province to decide whether to use daylight time, and not all do. As of 2006, with a few exceptions, most jurisdictions in Canada and the U.S. have been moving their clocks ahead by one hour on the first Sunday of April, and then back an hour on the last Sunday of October.

But beginning in 2007, daylight time will begin earlier and end later in the United States and in most jurisdictions in Canada. U.S. President George W. Bush signed legislation in August 2005 calling for daylight time to start on the second Sunday in March, three weeks earlier than the traditional start. The bill also extends daylight time by a week to the first Sunday in November.

This new schedule was introduced to try to help save energy, since people aren't expected to need their lights on as early in the evening. But there is still some debate about how effective the change will be at reducing energy consumption.

Eight provinces and two territories say they will follow the U.S. plan and begin daylight time earlier and end it later. Saskatchewan, Newfoundland and Labrador, and Nunavut have not indicated whether they will follow suit. Ontario has said not doing so would create too many headaches for trade and travel.

In Canada, areas of Quebec east of 63 degrees west longitude do not change to daylight time and remain on Atlantic Standard Time year round. Most of Saskatchewan uses Central Standard Time year round, and small pockets of Ontario and British Columbia do not use daylight time.

Daylight time is observed in most of the United States, with the exceptions of part of Arizona and part of Indiana. Much of Africa does not observe it, nor does China, Japan, the Indian subcontinent or Indonesia.

Some parts of Australia have adopted daylight time. Of course, it's done a little differently than in the Northern Hemisphere where seasons are opposite. So, when daylight time starts in Canada, it comes to an end in Australia and vice versa. When Canadians are waxing their skis in December, Australians are waxing their surfboards because it's summer there.

Criticism of DST

DST is not universally accepted and many localities do not observe it. Opponents claim that there is not enough benefit to justify the need to adjust clocks twice every year. The disruption in sleep patterns associated with setting clocks either forward or backward correlates with a small increase in the number of fatal road accidents[5] (cf. above estimate of net decrease in fatal road accidents of 50) as well as lost productivity as sleep-disrupted workers adjust to the schedule change,[6] although some believe that people in today's society do not get enough sleep as their body would naturally give them, and if this changed, then the increase in fatal road accidents would not be as high.[7]

It is also noted that much effort is spent reminding everyone twice a year of the change, and thousands are inconvenienced by showing up at the wrong time when they forget.[citation needed] Since DST exchanges morning daylight for evening daylight, late sunrises occur when DST is in effect during the parts of the year when days are shorter, and darkness in the morning can be undesirable for early risers like many schoolchildren and workers.

Astronomers refer to it as Darkness Squandering Time as it makes the observation of the night sky more inconvenient, and disadvantages children in astronomy who have to go to bed in time.

Complications from DST shifts

DST's twice-annual shifts in recorded time cause legal and business-operational complications, as shown in the following examples. During a North American time change, an autumn night during which clocks are reset from 2 a.m. DST to 1 a.m. Standard Time, times between 1 a.m. and 2 a.m. will occur twice, causing confusion in transport schedules, payment systems, etc.[citation needed] DST's annual autumn shift in recorded time—which causes an hour of the same numerical name to be recorded twice—also means that people born during one of those two hours have no way to know which of standard time or DST was used to record the time of their birth, unless someone such as a parent makes a note of it; birth certificates rarely keep track of this. A British politician, Lord Balfour, noted the legal complications in British law: "Supposing some unfortunate Lady was confined with twins and the first child was born 10 minutes before 3 o'clock British Summer Time. … the time of birth of the two children would be reversed. …Such an alteration might conceivably affect the property and titles in that House."[8].

Daylight saving time also causes much confusion with international business, people who commute across time zones, and computer networks that span multiple time zones. One particular problem for scheduling systems is that it makes the length of a day variable. Each year there is one 23 hour day and one 25 hour day, causing display and time tracking problems, especially when coordinating events between time zones.

These complications are moot if times & schedules are recorded with reference to Coordinated Universal Time (previously, Greenwich Mean Time), which is unaffected by Daylight Saving Time shifts.

Some studies do show that changing the clock increases the traffic accident rate. Following the spring shift to DST, when one hour of sleep is lost, there is a measurable increase in the number of traffic accidents that result in fatalities.[9] Critics argue that DST shifts put extra stress on human sleep-wake cycles—if people were allowed as much sleep as their bodies required on a regular schedule, it would cause a reduction in the number of fatal road accidents.[10]

DST is particularly unpopular among people working in agriculture[11] because they must rise with the sun regardless of what the clock says, and thus their schedules are placed out of synchronization with the rest of the community, including school times, broadcast schedules, and the like during the DST shift.

Other critics suggest that DST is, at its heart, government paternalism and that people rise in the morning as a matter of choice because many people enjoy night-time hours and their jobs do not require them to make the most of daylight. Different people start their day at different times (office workers start their day later than factory workers, who start their day later than farm workers), regardless of daylight saving time.

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posted by u2r2h at 7:22 PM


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