Pardon me, do you have the time?

What time is it in your part of the world?
Did you change your clocks recently, or are you about to?

If you live in the U.K., you have changed your clocks at 2am on Sunday, March 31. The rest of the European Union countries also make this change to Summer Time – as Daylight Saving Time is called in Europe.

Who changes when?
Of the more than 70 countries whose citizens adjust their clocks one hour forward in summer, these dates are the most commonly observed: from the last Sunday in March to the last Sunday in October.

However, Daylight Saving Time (DST) observance varies widely. China does not observe DST at all, nor do most countries located close to the equator. Southern Hemisphere countries that change – such as Chile, Uruguay, and New Zealand – do so in accordance with their seasons. Therefore, their DST is the reverse of that observed in the Northern Hemisphere. For example, New Zealanders move their clocks forward on the last Sunday in September, and move them back on the first Sunday in April.

In Brazil, only part of the country observes DST. In the Eastern Time Zone region, which includes the cities of Rio de Janeiro, São Paulo, Brasilia, Bahia, Minas Gerais and Rio Grande do Norte, clocks are moved forward on the third Sunday in October, and moved back on the third Sunday in February.

As of 2011, the Falkland Islands observe DST all year. Previously, Falkland Islands Summer Time (FKST) was observed from the first Sunday in September through the third Sunday in April. But two years ago, the Legislative Assembly determined that year-round DST would create more business day overlap between the Falklands and Europe, and longer days during winter months.

While the day to change clocks is overwhelmingly a Sunday, there are exceptions. In Israel, clocks are moved forward on the Friday before the last Sunday in March.  Israel Summer Time, as it is called, ends on the first Sunday after October 1.

What are the reasons and consequences?
What began as a way to conserve resources is a practice that has been in effect for nearly 100 years. From saving fuel during World War I to powering down electrical lights and air conditioning in modern times, the concept has gone a step further in some places. In 2007, U.S. President Bush signed an energy bill into law, extending DST by a month. It now starts three weeks earlier in the spring and ends one week later in the fall. U.S. clocks moved forward on March 10 this year.

It may help conserve power for a few more weeks, but business travelers accustomed to a certain time difference between the U.S. and the U.K., for example, now have to factor in this additional change for those four weeks.

To make things even more interesting, not all U.S. states observe DST. Arizona does not move its clocks, nor does Hawaii. Arizona legislatures puts forth a very good argument, due to its very high summer temperatures, for keeping the clocks on standard time and allowing at least one evening hour to be darker – and cooler.

And sound reasoning that might be. But travelers to and from Arizona are sometimes confused by the fact that although it is in the U.S. Mountain Time zone, for those summer months during DST, it is in line with Pacific Time.

Confusion is only part of the story. Despite well recognized claims that the extra hour of daylight helps decrease accidents, spikes in workplace injuries, vehicle accidents, and even heart attacks have been recorded in the week following the DST clock change.

Nevertheless, DST is embraced by many, and the biannual clock change also provides an opportunity for safety reminders, like changing the batteries in home smoke alarms.

Keeping time
For those doing business around the world – whether traveling or via conference call – some preparation and the right tools can help it all go smoothly.

For example, the World Clock Meeting Planner lets users select the right time across two or more locations. This tool can be used online or in app form. There are many other sites and apps that convert time to other locations.

The auto-adjust feature that all electronics carry these days make it easy to personally keep track of our own time. Our phones, laptops, and other devices automatically reset the time at the beginning and end of DST, based on our default time zone.

But when you are traveling AND dealing with a time change, it gets trickier. A simple app, widget, or online tool is best. After all, if you have a flight to catch from London back to Santiago this Sunday morning, you may have some foggy recollection of the DST change the night before, but your sleepy brain and body will need all the help it can get to make that plane.

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