[tz] How can I add a new time zone: 'America/Joao Pessoa'?

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Sun Jan 31 23:38:44 UTC 2021


On 2021-01-31 15:39, Fabrício Cabral wrote:
> On Sun, Jan 31, 2021 at 7:30 PM Guy Harris wrote:
>> On Jan 31, 2021, at 2:13 PM, Fabrício Cabral wrote:
>>> How can I add a new time zone? I'd like add 'America/Joao Pessoa'. Joao 
>>> Pessoa[1] is the capital of Paraiba state, in Brazil.

>> The first step would be to give the history of time zone changes in the 
>> region that contains it, indicating how its history differs from that of 
>> other tzdb regions in Brazil (America/Noronha, America/Belem, 
>> America/Santarem, America/Fortaleza, America/Recife, America/Araguaina, 
>> America/Maceio, America/Bahia, America/Sao_Paulo, America/Campo_Grande, 
>> America/Cuiaba, America/Porto_Velho, America/Boa_Vista, America/Manaus, 
>> America/Eirunepe, and America/Rio_Branco), so that it requires a new region.

> The time zone changes are the same of America/Fortaleza, but nobody uses it
> as to configure time zone to João Pessoa because America/Fortaleza is further
> than America/Recife. So, by logic, Joao Pessoa people choose America/Recife
> instead of America/Fortaleza.
It appears to make little difference nowadays as those zones appear to have the 
same history except for a week in 2000; from southamerica:

...
# Decree 3,630 <http://pcdsh01.on.br/Dec3630.jpg> (2000-10-13)
# repeals DST in PE and RR, effective 2000-10-15 00:00.
# Decree 3,632 <http://pcdsh01.on.br/Dec3632.jpg> (2000-10-17)
# repeals DST in SE, AL, PB, RN, CE, PI and MA, effective 2000-10-22 00:00.
...
Rule    Brazil  2000    2001    -       Oct     Sun>=8   0:00   1:00    -
...
#
# Maranhão (MA), Piauí (PI), Ceará (CE), Rio Grande do Norte (RN),
# Paraíba (PB)
Zone America/Fortaleza  -2:34:00 -      LMT     1914
                         -3:00   Brazil  -03/-02 1990 Sep 17
                         -3:00   -       -03     1999 Sep 30
                         -3:00   Brazil  -03/-02 2000 Oct 22
                         -3:00   -       -03     2001 Sep 13
                         -3:00   Brazil  -03/-02 2002 Oct  1
                         -3:00   -       -03
#
# Pernambuco (PE) (except Atlantic islands)
Zone America/Recife     -2:19:36 -      LMT     1914
                         -3:00   Brazil  -03/-02 1990 Sep 17
                         -3:00   -       -03     1999 Sep 30
                         -3:00   Brazil  -03/-02 2000 Oct 15
                         -3:00   -       -03     2001 Sep 13
                         -3:00   Brazil  -03/-02 2002 Oct  1
                         -3:00   -       -03
...

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

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