
First, a quick clerical patch: 0001, attached, fixes the placement of a comment which got shuffled around in the lead-up to publishing the changes for South Sudan in 2021a. Patch 0003 relates to Tonga, and comes from some of the links P Chan shared to 1957–1963 editions of The Air Almanac: https://mm.icann.org/pipermail/tz/2021-February/029866.html On Thu, 25 Feb 2021 at 03:43, P Chan <legco@outlook.com> wrote:
1960 Nov (1962.1-4) https://books.google.com/books?id=bVgtWM6kPZUC&pg=SL1-PA20 1961 Mar (1962.5-8) https://books.google.com/books?id=W2nItAul4g0C&pg=SL1-PA20
When looking around at how this data was presented for other regions, I noticed on the preceding pages (listing "Places Fast on GMT", i.e., east of Greenwich) in some of the earlier editions provided that Tonga was listed at GMT+12:20. The peculiar offset stuck out, and I quickly noticed that some of the later editions of the same tables had it at GMT+13. A quick bisection puts the changeover, as far as The Air Almanac contemporaneously reckoned it, between November 1960 and March 1961. Previously, our data had Tonga transitioning to UT+13 in 1941 based on a quotation from a 1997 news article. Although this differs from what the Almanac suggests by some 20 years, the article does mention a change coincident with the New Year, and that Tāufaʻāhau Tupou IV was Crown Prince at the time. As his predecessor and mother, Queen Sālote Tupou III, reigned from 1918-04-05 to 1965-12-16, a possible transition of 1961-01-01 still jives with the gist of the article, even if the specific year was perhaps wrong or just misprinted. For what it's worth, our commentary already noted that Shanks & Pottenger had put the transition even later, at 1968-10-01. Although of course we don't know how they arrived at that date, given that they did, 1961 seems rather less out-of-place than it otherwise might. The attached patch 0003 makes this adjustment, while more fully documenting and comparing the conflicting sources. Thanks again to P Chan for pointing us to these resources. I wasn't expecting to get a "bonus" correction out of it, but one never knows quite what will catch the eye… -- Tim Parenti

On 2021-03-03 03:59, Tim Parenti via tz wrote:
A quick bisection puts the changeover, as far as The Air Almanac contemporaneously reckoned it, between November 1960 and March 1961.
Previously, our data had Tonga transitioning to UT+13 in 1941 based on a quotation from a 1997 news article. Although this differs from what the Almanac suggests by some 20 years, the article does mention a change coincident with the New Year, and that Tāufaʻāhau Tupou IV was Crown Prince at the time. As his predecessor and mother, Queen Sālote Tupou III, reigned from 1918-04-05 to 1965-12-16, a possible transition of 1961-01-01 still jives with the gist of the article, even if the specific year was perhaps wrong or just misprinted.
For what it's worth, our commentary already noted that Shanks & Pottenger had put the transition even later, at 1968-10-01. Although of course we don't know how they arrived at that date, given that they did, 1961 seems rather less out-of-place than it otherwise might.
While you are at it, let me quote [Ian R Bartky: "One Time Fits All: The Campaigns for Global Uniformity". Stanford University Press. 2007. p 24..26]: 3. On 10 September 1945 Tonga adopted a standard time 12 hours, 20 minutes in advance of Greenwich. On 19 October 1960 the legislation was amended by shifting to a time 13 hours in advance, and continuing the Eastern reckoning of the days. Tonga's daylight saving time, observed in 1999 and 2000, was abandoned by 2002. I thank Rhys Richards for these dates. This implies that tzdb is wrong for Tonga at least from 1945-09-10 until 1960-10-19, and it is compatible with your proposal for the switch to UT + 13:00 at 1961-01-01. And it suggests that the switch from LMT to UT + 12:20 should be advanced from 1901 to 1945-09-10. Michael Deckers.

On 3/3/21 8:10 AM, Michael H Deckers via tz wrote:
[Ian R Bartky: "One Time Fits All: The Campaigns for Global Uniformity". Stanford University Press. 2007. p 24..26]:
3. On 10 September 1945 Tonga adopted a standard time 12 hours, 20 minutes in advance of Greenwich.
Thanks, proposed patch attached and installed into the development repository.

On Wed, 3 Mar 2021 at 11:10, Michael H Deckers < michael.h.deckers@googlemail.com> wrote:
While you are at it, let me quote
[Ian R Bartky: "One Time Fits All: The Campaigns for Global Uniformity". Stanford University Press. 2007. p 24..26]:
3. On 10 September 1945 Tonga adopted a standard time 12 hours, 20 minutes in advance of Greenwich. On 19 October 1960 the legislation was amended by shifting to a time 13 hours in advance, and continuing the Eastern reckoning of the days. Tonga's daylight saving time, observed in 1999 and 2000, was abandoned by 2002. I thank Rhys Richards for these dates.
I wasn't finding this quote on the pages specified in the previews on Google Books, so I borrowed the hardcover copy from my institution's library. Perhaps it amounts to a difference in editions, but I see this text as part of endnote 3 in the "Epilogue" section, on page 255, which seems to be more inline with the Google version, too. The second sentence of this quotation further supports what the Air Almanac points to regarding a 1961 change. In the main text that the endnote supports, as part of a discussion about the (apparently unintentional) race "to be the first in the world to see the dawn of the new millennium", Bartky says that "since 1961 [Tonga's] official time has been thirteen hours in advance of Greenwich time" (p. 202) which further supports our suspicion that the effective date of the transition was 1961-01-01. Since this helps us to better sum up what we know, I've installed the attached patch to commentary. -- Tim Parenti
participants (3)
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Michael H Deckers
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Paul Eggert
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Tim Parenti