All, I'm working on a proposed patch focusing on the data in the table provided since 1939-10-01, but it is taking a bit of time to ensure I'm getting it right. Combined with more information on the pre-1939 laws above, this will be very useful. -- Tim Parenti On 31 January 2018 at 19:23, Paul Eggert <eggert@cs.ucla.edu> wrote:

On 01/30/2018 10:32 PM, Jeremie Bonjour wrote:

...

I submitted this information because it is not correct on the iana. org website.

Thank you for the informationi. I installed the attached patch to document the SOHMA almanac. Could you please help me interpret Table 6.3 (page 36) so that we can correct the tz data? The first few entries of Table 6.3 look like this:

...

DESDE: 27-Jun-1908 HASTA: 30-Apr-1920 LEY O DECRETO: Dto. Reglamentario de Ley No 3290 12-Jun-1908.

Is this law available online somewhere? We will probably need to refer to it to get details about exactly when the transitions occurred.

...

DESDE: 1-May-1920 HASTA: 30-Sep-1923 HUSO HORARIO: +4h.* LEY O DECRETO: Ley No 7200 26-Apr-1920

Similarly, is this law available online? We will need to refer to it, to find the dates and times of the daylight-saving transitions.

...

DESDE: 1-Aug-1923 HASTA: 31-Mar-1926 HUSO HORARIO +3h. VERANO +3h.30m INVIERNO LEY O DECRETO: Ley No 7594 28-Jun-1923

The second line says "HASTA: 30-Sep-1923" and the third line says "DESDE: 1-Aug-1923"; how can both laws be in effect during August and September 1923?

Many of the later entries are like "Dto.No 24233 del MDN 21-May-1959"; where can we find these online?

I must admit, over the last fortnight, I did a bit more spelunking into the depths of Uruguayan law than I was initially expecting. The result is the attached proposed patch. The records were actually quite accessible, and typically straightforward to transcribe and translate. Although the dates listed in Almanaque 2018 correspond to when the various laws and decrees were made, they were typically published in the Diario Oficial some time later. Since the changes were generally promulgated on short notice, such publication often occurred after the changes took effect. But at least the Almanaque, or its primary sources, did a good job of compiling references to all the various laws and decrees. In general, even with a limited understanding of Spanish, simply looking for "hora legal" in the index summaries of each day's Diario in the online archives <http://www.impo.com.uy/diariooficial/> made it fairly easy to find the documents I looked for. Of course, there are nearly 50 such documents from the last 110 years that are referenced by the Almanaque in its compilation. Although I did not independently verify every single one of these, there is sufficient context in the oldest and newest ones to suggest that most, if not all, transitions prior to 2005 were at midnight. Additionally, the vast majority of the dates given by Almanaque are Sundays, so Sunday 00:00 transitions are generally assumed as correct, as this is consistent with early laws as well as much of what we already had. There are, however, a few exceptions where Almanaque listed a Saturday or a Monday instead; in these cases, the relevant legal documents do, in fact, confirm those dates. Details are given in the proposed commentary changes to southamerica. A few typos in Almanaque's compilation (and, though I don't mention them, even in some early laws!) were also uncovered, but the references were solid enough that reasonable confidence could be established in the data presented in the patch. Unsurprisingly, it turns out that most of the original data from Shanks & Pottenger is easily refutable. This results in significant changes to timestamps prior to 1991, which are detailed a bit more in the proposed additions to NEWS. Of particular note, there were four different offsets during the calendar year 1974, rendered as four different DST amounts (0, 30, 60, and 90 minutes, though not in that order). -- Tim Parenti

  On 2018-02-16 17:58, Paul Eggert proposed:

+# .......  Assume transitions at 24:00 on the specified days until Ley No. +# 7919 of 1926-03-05 ended this arrangement, repealing all "laws and other +# provisions which oppose" it, resulting immediately in year-round UT-03:30. +# (Since we don't know the time at which the change became law, assume clocks +# were changed at 24:00 that evening.  Almanaque 2018 is a bit hand-wavey here, +# anyway.) +#....... +# https://www.impo.com.uy/diariooficial/1926/03/10/2 +#....... +Rule    Uruguay    1926    only    -    Mar     5    24:00    0  -

  The proposed date of the switch, 1926-03-06, would be before the publication   of the law, which seems to be unlikely. Anyway, the Almanaque 2018 explicitly   says that the switch was on 1926-04-01, the date specified by the law of 1923,   and so does the Resolución of 1926-03-11 published in       [http://www.impo.com.uy/diariooficial/1926/03/18/2].   I propose that tzdb follow these sources, rather than make an estimate.   Michael Deckers.

(Actually, with this, it turns out that no 1926 timestamps are changing relative to 2018c, so this updated patch also makes the relevant change to NEWS.) -- Tim Parenti On 20 February 2018 at 10:01, Tim Parenti <tim@timtimeonline.com> wrote:

Thanks for that, Michael. I had missed that Resolución and didn't think to look for it, since it wasn't directly referenced by the Almanaque. The original reason for the guesswork there was simply that the 1926 law, unlike most of the others, didn't explicitly give a transition time in its text or nearby, and the Almanaque's loose "VERANO/INVIERNO" notations didn't themselves lend a lot of confidence in the dates given for that era.

I certainly could have been a bit more thorough in looking through the Diario for nearby dates. Further proposed patch attached.

Thanks again.

-- Tim Parenti

On 20 February 2018 at 08:51, Michael Deckers < michael.h.deckers@googlemail.com> wrote:

...

On 2018-02-16 17:58, Paul Eggert proposed:

+# ....... Assume transitions at 24:00 on the specified days until Ley

...

No. +# 7919 of 1926-03-05 ended this arrangement, repealing all "laws and other +# provisions which oppose" it, resulting immediately in year-round UT-03:30. +# (Since we don't know the time at which the change became law, assume clocks +# were changed at 24:00 that evening. Almanaque 2018 is a bit hand-wavey here, +# anyway.) +#....... +# https://www.impo.com.uy/diariooficial/1926/03/10/2 +#....... +Rule Uruguay 1926 only - Mar 5 24:00 0 -

The proposed date of the switch, 1926-03-06, would be before the publication of the law, which seems to be unlikely. Anyway, the Almanaque 2018 explicitly says that the switch was on 1926-04-01, the date specified by the law of 1923, and so does the Resolución of 1926-03-11 published in [http://www.impo.com.uy/diariooficial/1926/03/18/2]. I propose that tzdb follow these sources, rather than make an estimate.

Michael Deckers.