[tz] Historical fix for Tonga
Michael H Deckers
michael.h.deckers at googlemail.com
Wed Mar 3 16:10:33 UTC 2021
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
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.
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