[tz] Error for Chile on September 2023

[Brian Inglis]

On 2023-11-06 15:47, Doug Ewell via tz wrote:
> Guy Harris wrote:
>>> 2. Starting at midnight on the first Saturday of the month of
>>> September 2023 and until midnight on the first Saturday of the month
>>> of April 2024, the official time will be advanced by 60 minutes.

>> Presumably meaning "Starting at midnight at the end of the first
>> Saturday of the month of September 2023", as the last Rule entry for
>> Chile is

>> 	Rule    Chile   2023    max     -       Sep     Sun>=2  4:00u   1:00    -

> Correct and understood; the decree’s “midnight on [viz. at the end of]
> Saturday” (here, the 2nd) is equivalent to my “midnight at the start of
> Sunday” (here, the 3rd). But it could not refer in any way to the 11th.
The rules use Sun >= 2 becuse the time specified with "u" is UTC not local, it 
is the same as Sun >= 1 (1st Sunday) in local time; and Sun >= 9 Z => Sun >= 8 
local (2nd Sunday) in 2022 only.

So Sun 3 & 10 would be "4" & "11" for these rules.

I think the OP has generalized from a single data point, and may think the 2022 
change on 2nd Sunday was meant to continue, but that was reverted for 2023 on:

Rule    Chile   2019    max     -       Apr     Sun>=2  3:00u   0       -
Rule    Chile   2019    2021    -       Sep     Sun>=2  4:00u   1:00    -
Rule    Chile   2022    only    -       Sep     Sun>=9  4:00u   1:00    -
Rule    Chile   2023    max     -       Sep     Sun>=2  4:00u   1:00    -

See https://github.com/eggert/tz/blob/main/southamerica#L1318 for Chile's DST 
history

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry