Why is Singapore in the “Wrong” Time Zone?

The short answer is that West Malaysia follows the time zone for East Malaysia, and that Singapore follows West Malaysia. But it is even more complex than that! Some years ago I created a page based on information from the file asia, which is part of the tz database. After giving a lecture on the Chinese calendar at the Department of History at the National University of Singapore I got in touch with Mok Ly Yng, who has researched this extensively, and corrected some errors in the tz database. I have therefore replaced this page with the article he sent me. Mok Ly Yng has also helped me with the page Where is the Geographical Origin Point of Singapore?

The time zones in Singapore and Malaysia are good examples of how the lines between time zones tend to creep westward over the years. In other words, a place that's near the eastern edge of a time zone is likely to move its clocks ahead one hour, thereby moving to the western edge of the adjacent time zone.

I have a separate page on Time Zones in Malaysia. For information about time zones in Indonesia, please consult Indonesia Time Zones by Gwillim Law.

What time is it really?
by Mok Ly Yng

“What time is it?” As a famous beer commercial has it. Nowadays what time is it really depends more on the lawyers, economists, politicians and businessmen and much less on the astronomers, geographers, surveyors, mathematicians and scientists like in the 19th century and before. To modularise this story, I have tabulated the chronological adoption of different “Standard Time” in Singapore as a quick reference:

“Standard Time” in Use in Singapore

Period in use Time offset from GMT Reference Meridian Name of Time (unofficial)
Until 1905 May 31 + 6hr 55m 25s 103 51 16 E Singapore Mean Time
1905 Jun 01 - 1932 Dec 31 + 7hr 00m 00s 105 00 00 E Standard Zone Time
1933 Jan 01 - 1941 Aug 31 + 7hr 20m 00s 110 00 00 E Daylight Saving Time
1941 Sep 01 - 1942 Feb 15 + 7hr 30m 00s 112 30 00 E Daylight Saving Time
1942 Feb 16 - 1945 Sep 12 + 9hr 00m 00s 135 00 00 E Tokyo Standard Time @
1945 Sep 13 - 1981 Dec 31 + 7hr 30m 00s 112 30 00 E DST/MST/SST # @
1982 Jan 01 - Present + 8hr 00m 00s 120 00 00 E Singapore Standard Time

@: The official duration of the Japanese Occupation was from 16-Feb-1942 to 05-Sep-1945. Although history books say that Singapore surrendered on 15-Feb-1942, the Japanese did not enter Singapore in force until the next morning, on 16-Feb-1942. This was agreed to by both sides during the surrender negotiations. The starting date of switching to Tokyo Standard Time is fairly certain but not the ending date. Japan announced their surrender on 15-Aug-1945. The official surrender ceremony took place on 02-Sep-1945. On 06-Sep-1945, advanced parties of British troops entered Singapore, officially ending the Japanese Occupation. On 09-Sep-1945, Operation Zipper took place on the west coast of Malaya, this involved the landing of the main British forces to recapture Malaya. But it was not until 12-Sep-1945 that the official surrender ceremony for Japanese troops in the SE Asian region took place at the Padang in Singapore. By pure speculation, the most probable dates for reverting to “Pre-invasion” time would either be 03-Sep-1945 or 13-Sep-1945, 1 day each after the respective official surrender ceremonies.

#: DST = Daylight Saving Time, MST = Malaya/Malaysia Standard Time, SST = Singapore Standard Time.

If you do not have the time to read more, the above is a succinct summary of the whole story. For those who would like to know a little more, I shall continue with a more detailed description of the adoption dates and background for the various “Standard Times” in use.

Brief Background of Malaya

By the turn of the 20th century, there were 3 major political entities present in Malaya. The Crown Colony of the Straits Settlements (SS), comprising of Penang, Province Wellesley, Malacca and Singapore. The Federated Malay States (FMS), which included the modern-day Malaysian states of Perak, Pahang, Selangor and Negri Sembilan. Finally, the Unfederated Malay States (UMS), which was the collective name for the States of Perlis, Kedah, Kelantan, Trengganu and Johore.

The Straits Settlements had the strongest British presence, followed by the FMS and lastly the UMS, which essentially were more or less self-ruling by their respective Sultans. The term “Malaya” includes all 3 entities—SS, FMS and UMS.

History of Singapore Standard Time

Before 1st Jan, 1901, locations in Malaya with an Astronomical Observatory would adopt the local mean time based on the Observatory's geographical position. Penang, Malacca and Singapore all had their own observatories, hence the three Straits Settlements had their respective Local Mean Time, with minutes of differences amongst the three locations.

1901. On 1st Jan 1901, Singapore's Local Mean Time (Singapore Mean Time) was adopted by the Straits Settlements and the Federated Malay States as the Standard Time. This was introduced because railway, postal and telegraphic services were becoming more common and a single standard time will ease scheduling problems. Singapore was chosen because it was the administrative HQ for the SS and the FMS then.

1905. On 1st June 1905, the mean time of the 105th Meridian (Longitude 105 deg East) was adopted by the Straits Settlements and the Federated Malay States as the new Standard Time. This decision was made way back in February, 1904. The mean time of the 105th meridian is 7 hours ahead of Greenwich Mean Time (i.e. the Local Mean Time over Greenwich Royal Observatory near London, England). This Standard Time went into effect when the Time Ball on Fort Canning was completed and became operational on the same day.

Back in 1884, 25 governments of the world got together in Washington, DC for the International Meridian Conference and decided upon the adoption of time zones around the world as we know it today. 22 approved, 1 objected and 2 abstained. The longitude passing through Greenwich's Royal Observatory was chosen to be the Prime Meridian, the 0 or starting point for global longitude and time determination. The world was divided into 24 time zones, each 15 deg wide and covers 1 hour of time. Each zone's Standard Time is based on the central meridian of the zone being multiples of 15 deg (= no. of hours) away from the Prime Meridian. 105 / 15 = 7, hence 7 hours ahead of GMT. [Why 15 deg in 1 hour? It is because 15 x 24 = 360 deg for a complete circle around the Earth.]

1920. In 1920, a bill was introduced in the SS Legislative Council to adopt “Daylight Saving Time” just like in England. The proposed time was 30 min forward of the mean time of the 105th meridian, i.e. 7hrs 30 mins ahead of GMT. The reason for proposing this was to allow more leisure time for the labourers after work. Unfortunately, this bill was dropped after the first reading.

1932. 12 years after the 1920 introduction of the “Daylight Saving Bill”, the same bill was reintroduced to the Legislative Council. One of the original reasons for dropping the 1920 Bill was the argument that 30 min was too much change. So, in 1932, the proposed shift was reduced by 10 min, down to 20 minutes ahead of the mean time of the 105th meridian. This was a compromise which was perceived to be more acceptable to the overly cautious Legislative Council members. After 2 debating sessions, this Bill was passed and became Ordinance No. 21 of 1932. The short title was Daylight Saving Ordinance, 1932. This was to come into force on the first day of January, 1933, and was to be in force during the year 1933.

1933. 1st Jan 1933, the Daylight Saving Ordinance came into effect on New Year's Day. This Ordinance as passed was in effect for the year 1933 only. Daylight Saving Time was 20 minutes faster than Standard Time, i.e. 7 hrs 20 mins ahead of GMT.

1934-1935. For the years 1934 and 1935, the Daylight Saving Ordinance, 1932 was extended throughout both years by Gazette Notifications.

1935. In 1935, the Daylight Saving Ordinance, 1932 was amended by Ordinance No. 5 of 1935--The Daylight Saving (Amendment) Ordinance, 1935. The year limit '1933' was removed, turning the ordinance into permanent effect without the need for the Governor to declare any extensions. The time of 7 hrs 20 mins ahead of GMT became permanent “Standard Time” with this amendment. The Survey Department's 1935 Annual Report advised readers to adjust their clocks appropriately by 20 min for the year 1936.

1936. The Daylight Saving Ordinance became Chapter 170 in the 1936 Edition of The Laws of the Straits Settlements.

1941. In 1941, the Daylight Saving Ordinance was amended yet again by Ordinance 33 of 1941. Daylight Saving Time would henceforth be 30 min ahead of the mean time of the 105th meridian (10 min more than the original DST), i.e. 7 hrs 30 min ahead of GMT. This came into effect on 1st Sep 1941. Interesting to note that this was the original DST proposed in 1920 and was met with much opposition then.

1942. 16th Feb 1942, Japanese formally occupied Singapore. Singapore time moved ahead by 1 hr 30 min to conform with Tokyo Standard Time, which is 9 hours ahead of GMT.

1945. 12th Sep 1945, Japanese formally surrendered in Singapore. Singapore time reverted to “pre-invasion” standard: 7 hrs 30 min ahead of GMT. The exact dates for the change to and from Tokyo Standard Time have not been ascertained yet. The dates given here are based on educated speculation.

1955. In The Laws of the Colony of Singapore published in 1955, the Daylight Saving Ordinance was renumbered Chapter 266. In the same publication, under Chapter 2, Interpretation and General Clauses, Section 41(2) defined what was the “Standard Time” in Singapore -- 7 hrs 30 min ahead of GMT.

1970. In the 1970 edition of The Statutes of the Republic of Singapore, Chapter 266 (Daylight Saving Ordinance) was omitted. In this edition, Standard Time in Singapore was defined only once in the renumbered Interpretation Act, Chapter 3, Section 52(2). Thus, sometime in between 1955 and 1970, the Daylight Saving Ordinance was repealed and the faster Daylight Saving Time was redefined as the Standard Time of Singapore, replacing that of the 105th meridian's mean time. This could have come about from a variety of events, namely the independence of Malaya in 1957, self-rule for Singapore in 1959, merger and formation of Malaysia in 1963 and the independence of Singapore in 1965. Throughout these episodes, the time remained at 7 hrs 30 mins ahead of GMT, both in Malaya/Malaysia and Singapore. Each of the events could have redefined the Standard Time's official name and was later inherited by Singapore.

1981. Sometime in 1981, Malaysia declared that West Malaysia would move their clocks ahead by 30 min to match the time in use in East Malaysia (8 hrs ahead of GMT). This meant that Singapore would be in a rather awkward position in time if she didn't follow suit, especially with the amount of traffic and trade across the causeway. Singapore Government Gazette Notification S 392/81 (dated 31 December 1981) notified the nation that as of 1st Jan 1982, Singapore Standard Time would be 8 hours ahead of GMT.

1982. 1st Jan 1982, at 4 o'clock GMT, in the afternoon of 31st December 1981, Singapore Standard Time became 12 midnight (4 + 8 = 12). 1985. In the 1985 edition of The Statutes of the Republic of Singapore, the Interpretation Act was renumbered as Chapter 1. Standard Time was defined in Section 52(2).

1999. In the 1999 revised edition of The Statutes of the Republic of Singapore, Standard Time was defined under The Intepretation Act, Chapter 1, Section 51(2).

2000. In the 2000 edition of the Subsidiary Legislation under the Interpretation Act (Chapter 1, Section 51(2)). CAP.1, N1, Singapore Standard Time Notification, para 2 “Standard Time” reads “The standard time in Singapore shall be 8 hours in advance of Greenwich mean time.”

Other Time Zone Related Stories

1995. In 1995, it was proposed by ASEAN leaders that an ASEAN Common Time (ACT) be adopted and it was later suggested that this would only be implemented for all the capital cities of ASEAN. A year later, in 1996, at the first informal meeting of the Heads of Government of ASEAN in Jakarta, the Heads of Government agreed to review the matter during the period of 2000-2003.

2001. In July 2001, Thailand announced their intention of moving their clocks forward by 1 hour, to be in line with both Malaysia and Singapore, but more importantly, to be on the same time as China and Hong Kong, i.e. 8 hrs ahead of GMT.

Singapore is currently in effect running on the equivalent of the usual 'Spring Forward, Fall Back' type of Daylight Saving Time found in North America and Europe. Such 'normal' DST is usually Standard Zone Time + 1 hour. Singapore's mathematical Standard Zone Time is 7 hr (105th meridian), hence the current 8 hrs is = 7 + 1 which is equivalent to the DST during the Summer months in the temperate countries. Albeit we are on this DST throughout the year, quite appropriate since we have 'summer' all year round.

During the Japanese Occupation, Singapore's local time was 2 hours ahead of the Standard Zone Time of 7 hours. This is known technically as the Double Summer/Daylight Time. Nothing quite out of the ordinary in fact. Throughout WW2, Britain was running on Double Summer Time or War Time, i.e. Standard Zone Time + 2 hrs. The USSR as a whole continued their DDT until 1989 when the Soviet Union broke up and it was realised that they had somehow either forgotten or taken for granted about returning to Standard Time after WW2! Talk about no sense of time...

Nowadays, the time standard in Singapore is maintained by the Productivity and Standards Board (PSB). The maintainer of time in Singapore is another story on its own. It covers the Harbour Board, the Survey Department, the Royal Navy, US Navy and a few other agencies.

PS: I had prepared three graphics for my intended 'technical report' but I thought they should accompany this write-up to help in visualising some of the technical details.


Shows the theoretical division of time zones around the world. If you have a time zone map (travel guidebooks; insurance diary; atlas etc.), compare it with this map and you'll see that China is about the only country left in the world which spans across multiple theoretical time zones but maintains only 1 single time within its political boundaries. You might also be interested in the use of the Alphabets to denote time zones.


Note that the Chinese cities of Kunming, Chengdu and Chongqing actually lie within Zone +7, same as Singapore, in theory. These cities are attracting more businesses there due to the Great Northwestern Development scheme currently proposed by the Chinese government. Note also the location of Tokyo and the time zone the city is in. Seoul is geographically (theoretically) within Zone +8 but probably due to early Japanese annexation in the 1900's, Korea peninsular is running the same as Tokyo time in Zone +9. The reference observatory in China used to be in Nanjing.


This map shows the historical time standards adopted by Singapore and the corresponding reference meridians. Note that the majority of ASEAN Capital cities are in Zone +7, only 2 in Zone +8 and one in Zone +6. Rangoon is on +6:30 time, which is very close to the theoretical value. Geographically, ASEAN spans 4 time zones: +6,7,8,9. It would be interesting to see the outcome of the ASEAN Common Time review. Would everyone move to Zone +8 time or a compromise be reached which will necessitate another time change? But China could also contribute to a future time change. If she should decide to adopt time zones within the country, that could determine the time to be adopted for ASEAN countries in the future. Well, like I said, time adoption is more business than science in this present day and age.

Helmer Aslaksen
Department of Mathematics
National University of Singapore

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