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 This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]