Saturday, January 31, 2009

Is Singapore on Permanent Daylight Saving Time?

Though many ex-pat workers had observed that at 6 in the morning Singapore is kind of dark when compared to Hong Kong’s. Is this a sign of a permanent Daylight Saving Time?


By: Vanessa Uy


Given that longitudinally, the island nation of Singapore should have been in sync with Bangkok, Thailand’s standard time. Why is it then that Singapore chose to follow Hong Kong’s time zone? Are the reasons economically driven – rather than geographical – like the standard-time boundaries of the United States, which are designated by the Interstate Commerce Commission? But first, let us examine the concepts behind a country’s geographic location and it’s designated time zone.

The local time for any place on Earth depends upon its geographic longitude. The local time is set less advanced than that of Greenwich Mean Time by 1 hour for each 15-degree of longitude west of the Greenwich 0-degree meridian. This is so because it takes 24 hours for our Sun to “circumnavigate” – due to the Earth’s rotation – across the globe. Which turns out to be 360 degrees given the circular circumference of our planet. Dividing 360 degrees by 24 hours works out to 15 degrees per hour or each time zone is 15 degrees wide. Barring the now mandatory “occasional” leap-second corrections via the now widespread use of ultra-accurate atomic clocks, longitude west of Greenwich is determined by subtracting the local mean solar time – obtained by astronomical observation – from Greenwich Mean Time obtained from radio time signals.

To avoid continuous changes in time with longitude, Earth is divided into 24 zones. Within each zone, the same standard time is kept. Minutes and seconds are kept identical in all standard-time zones; only the hours differ. The time zone boundaries over land areas quite often zigzag in order to avoid inconvenient changes of time within geographic borders legally defined by various nation-states.

In some areas, time zones are used wherein the time may differ by 30 minutes – like the Indian Standard Time. Or by an odd number of minutes and seconds of Greenwich Mean Time – these are not considered standard time zones, however. While countries very near the north and south poles where the meridians converge and there is no single time zone, they customarily default to Greenwich Mean Time.

Given that since her independence, Singapore’s stock exchange has always operated in sync with Hong Kong Standard Time – rather than that of Bangkok, Thailand which supposedly is where Singapore’s geographic meridian is in parallel with – the probable expense of syncing with Bangkok Standard Time could prove to be too costly. Thus Singapore had always stuck with Hong Kong Standard Time – in spite of the “gripes” of the island state’s resident’s circadian rhythms and Old-School Feng Sui practitioners. Which is kind of disconcerting since Singapore’s near-equatorial location doesn’t allow the island state to have seasonal variations like that of lands located further up north the need to save energy intended for use in lighting purposes – the supposed raison d’être of Daylight Saving Time.

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