The Actual Time now

[2] Although formal nominations were made after Tokyo time, it was customary to keep two distinct times: the preoccupation time at home and Tokyo time on individual watch.

By the end of the Second World war and the British returned to Malaysia, Singapore had returned to its pre-war period. Though Singapore, due to its tropic position, does not currently follow summer time in the conventional meaning, a 20-minute summer time method was adopted by the Legislative Council of Straits Settlements in 1933.

1932 Sir Arnold Robinson[3] summed up the 20-minute off-set concept after an early experiment was aborted in 1920, first suggested by Sir Laurence Guillemard for a 30-minute offset[4] The 20-minute off-set was officially introduced as the default time in Singapore in 1936[4] and on September 1, 1941, the off-set was extended to 30 minutes[5] just like the 1920 suggestion.

Malaysia in 1981 resolved to standardise the time in its areas to a single UTC+08:00. The amendment came into force on 1 January 1982, when Singapore went forward half an hours on 31 December 1981 at 23:30 and created the Singapore Standard Time (SST)[8] SST is eight 8 hrs ahead of unTC and is synchronised with Hong Kong, Taipei, Beijing, Manila and Perth.

contains a Singapore area in the zone.tab file:

date-time - summer time and best practice for the time zones

Actually, there is no fully satisfactory level for the time remaining. Conceptually, these are usually two kinds of time-date dates and it is easy to differentiate between them (not the above standards): "physical time" and "civil time". The " physic " moment of time is a point in the continual universe time axis that is dealt with by physicists (of course without considering the theory of relativity).

Civilian" time is a date time that follows civilian norms: A time is indicated here by a series of date time slots (Y,M,D,H,MM,S,FS) plus a time zone specifier (actually also a "calendar"; but let's say we limit the debate to the Greek calendar). One time zone and one calendars together (in principle) make it possible to switch from one display to another.

However, civic and physic timing are basically different kinds of sizes, and they should be kept conceptionally separate and handled differently (an analogy: array of byte and string). It is a bewildering topic, because we are talking about such interchangeable occurrences, and because citizens' lives are changing politically.

For example, John notes in his diary a memory for an incident at the time 2019-Jul-27, 10:30:00, TZ=Chile/Santiago, (which moved GMT-4, i.e. equals 14:30:00 14: 2019-Jul-27 UTC). 2019-Jul-27 10:30:00 Chile/Santiago = 2019-Jul-27 15:30:00 CET Time ? 2019-Jul-27 9:30:00 Chile/Santiago = 2019-Jul-27 14:30:00 CET Time ? Unless you know what John means terminologically when he said to the calender, "Please call me 2019-Jul-27, 10:30:00 TZ=Chile/Santiago", there is no right response.

Was he referring to a "civilian date time" ("when the watches in my town show 10:30 a.m.")? On the other hand he meant a "physical moment of time", a point in the continuous time line of our cosmos, we say "when the next sunlipse takes place". Some few date/time-APIs get this differentiation right: among them Jodatime, which is the basis for the next (third!) Java DateTime API (JSR 310).