October 30th, 2006

krazy koati

Ticking the time away

I thought I'd talk about Singapore and Daylight Saving Time, since there really aren't many reasons to talk about it. Singapore either never or always is on Daylight Saving Time, depending on your point of view. It's so close to the equator the length of daylight doesn't vary much. The difference between the earliest sunrise -- 6:46 am, around November 1 -- and the latest -- 7:17 am, February 12 -- is only about a half hour, and the difference between the earliest sunset -- around 6:50 pm, November 4 -- and the latest -- 7:21 pm, February 9 -- is about the same. There's not much advantage gained by moving the clocks in any direction.

This means on average the sun is at its highest point in the sky -- so close to directly overhead the difference isn't worth mentioning -- at about 1 pm, when you should dash indoors before either it rains or the direct heat causes you to burst into flames. If you went by mean solar time you'd expect noon to be when the sun was as high as it got, and therefore sunrise would be at about 6 am and sunset at 6 pm.

Well, and I'm cribbing from Professor Helmer Aslaksen, who's got a bundle of fascinating pages about things like this, from 1 January 1901, Singapore -- and the Straits Settlements and the Federated Malay States -- set local time as 6 hours, 55 minutes, 25 seconds ahead of Greenwich Time, which is what the longitude of Singapore (103 degrees east) implies, though it's hard not to suspect they were being a bit deliberately fussy. From the start of June, 1905, they rounded that to Greenwich plus 7 hours.

In the 1920s and 1930s Daylight Saving Time was debated, and after a long time debating moving the clock ahead 30 minutes, the Straits Settlements compromised on moving it ahead 20 minutes, from the start of January 1933. From 1 September 1941, this advanced another ten minutes. When the Japanese Occupation began, Singapore was put on Tokyo time, Greenwich plus 9 hours, but sometime after the Japanese surrender the city went back to pre-war time. From somewhere around September 1945 through the end of 1981, Singapore -- and western peninsular Malaysia -- had Greenwich plus 7 hours 30 minutes. When Malaysia decided to move its western half into the eastern time zone (generally, when places change time zones they join the one to the east) Singapore went along, eliminating 11:30 pm to midnight of 31 December 1931, and from 1982 Singapore has been at Greenwich plus 8 hours, or one hour ahead of what the sun might suggest.

During Daylight Saving Time in the United States, this means I'm exactly twelve hours ahead of my parents' time, but in five years they still haven't figured it out and just have the rough idea that my evening is sometime in their morning and vice-versa.

Trivia: Standard time had no legal force in the United States until 1917. Source: Keeping Watch: A History of American Time, Michael O'Malley.

Currently Reading: Manias, Panics, and Crashes: A History of Financial Crises, Charles P Kindleberger.