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.

History

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.

Schedule changed to save energy

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.

A 2006 report from the U.S. Department of Energy anticipated electricity savings of four-tenths of a per cent per day of extended daylight savings time, totaling three one-hundredths of a per cent of annual electricity consumption.

As to the environmental impact, the non-profit group American Council for an Energy-Efficient Economy estimated 10.8-million-tonne drop in carbon emissions.

Exceptions

Most Canadian provinces and territories say they will follow the U.S. plan and begin daylight time earlier and end it later. In general, the provinces agreed it was essential to co-ordinate with the U.S. and that not doing so would create too many headaches for trade and travel.

"We're not anxious to have a disconnect between us and our chief trading partner," said Ontario Premier Dalton McGuinty.

Most of Saskatchewan has not observed daylight time since 1966 and stays on Central Standard Time all year round. Some border towns follow the time schemes of their neighbours in Manitoba or Alberta.

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. Pockets of Ontario and British Columbia do not use daylight time.

Daylight time is observed in most of the United States.

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.

Y2K, Part 2

In 2000, much of the world waited in anxiety for the chaos expected from Y2K, the design flaw that meant early computers stored dates as two digits rather than four. There was widespread anxiety that, come the Millennium, computers would interpret the year 2000 — "00" — as 1900.

Companies spent millions to upgrade computers and make sure they were Y2K compliant, while the public waited, looking skyward for the planes that were supposed to drop from the sky after their computers failed.

The more dramatic predictions warned of massive computer failures, possible accidental nuclear launches and general worldwide anarchy.

Of course, none of that ever happened. The threat of the bug was widely overblown and everyone had time to prepare.

Now, in 2007, the computer world is waiting for what some call a "mini-Y2K": the effects that the new daylight time change may have on computers.

Unlike Y2K, this bug hasn't triggered such ominous predictions. At most, it looks to be no more than a slight bother for the general public, perhaps with a few missed meetings as peoples' schedules are thrown off.

Companies are more likely to suffer as date and time changes affect budgets, security, schedules and communications. Most companies have had time to get their systems up to date, but those that lag behind could find their extra daylight time comes with serious headaches.

Computer fixes available

Fixes are available for most electronics, whether computers or digital handheld gadgets.

Most electronics manufacturers, including Microsoft, Palm and Sun Microsystems Inc, have created software patches to adjust computer settings to the change. Most of these are easily accessible on the company's website.

Vista, Microsoft's newest operating system, is unaffected by the change.

Most tech experts advise the average consumer to just re-confirm any upcoming appointments and double-check that their clocks and calendars are in sync — they need not cower in fear of falling airplanes.

Medical malfunctions unlikely

Health Canada has warned of other, potentially more troublesome glitches. In a press release sent out just days before the change, Health Canada warned that the time change could also affect some medical devices.

While the statement says most devices will probably not be compromised, it does offer a brief list of those that may be affected:

• Implanted pacemakers and defibrillators
• Holter monitors
• Glucose monitors

However, Health Canada says there should be no risk to users of these machines, aside from the inconvenience of having internal timers reset.

People using devices with internal clocks or timers are advised to contact their doctor or the supplier/manufacturer of the device before the time change. As well, anyone using a medical device with an internal clock after the time change should check that the clock shows the correct time. Likewise, devices should be rechecked in the fall; first on the old changeover date of Oct. 28, and again on the new one, Nov. 4.

The warning is simply cautionary and no major health threats are expected.