* NEWS: Mention the change, and leave room for future Portugal fixes. * africa (Africa/Maputo): Tweak LMT to match London Gazette, and change CAT transition date to a guess of 1909. --- NEWS | 4 ++++ africa | 19 ++++++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/NEWS b/NEWS index 25d939f1..0d6a1513 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,7 @@ Unreleased, experimental changes Briefly: The main data form now uses %z. + Improve historical data for Portugal and possessions. Changes to data @@ -15,6 +16,9 @@ Unreleased, experimental changes the represented data: the generated TZif files are unchanged. Rearguard form still avoids %z, to support obsolescent parsers. + Some transitions for Portugal and possessions have been changed. + This affects timestamps for Africa/Maputo before 1909. + Asia/Almaty has been removed from zonenow.tab as it now agrees with Asia/Tashkent for future timestamps, due to Kazakhstan's 2024-02-29 time zone change. Similarly, America/Scoresbysund diff --git a/africa b/africa index a731dbee..695d66ed 100644 --- a/africa +++ b/africa @@ -1101,13 +1101,22 @@ Zone Africa/El_Aaiun -0:52:48 - LMT 1934 Jan # El Aaiún # Zambia # Zimbabwe # -# Shanks gives 1903-03-01 for the transition to CAT. -# Perhaps the 1911-05-26 Portuguese decree -# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf -# merely made it official? +# From Paul Eggert (2024-04-09): +# The London Gazette, 1903-04-03, page 2245, says that +# as of 1903-03-03 a time ball at the port of Lourenço Marques +# (as Maputo was then called) was dropped daily at 13:00:00 LMT, +# corresponding to 22:49:41.7 GMT; round this to UT+2:10:18. +# Conversely, the newspaper South Africa, 1909-02-09, page 321, +# says the port had just installed an apparatus that communicated +# "from the controlling clock in the new Observatory at Reuben Point ... +# exact mean South African time, i.e., 30 deg., or 2 hours East of Greenwich". +# Although Shanks gives 1903-03-01 for the transition to CAT, +# evidently the port transitioned to CAT after 1903-03-03 but before +# the Portuguese legal transition of 1912-01-01 (see Europe/Lisbon commentary). +# For lack of better info, list 1909 as the transition date. # # Zone NAME STDOFF RULES FORMAT [UNTIL] -Zone Africa/Maputo 2:10:20 - LMT 1903 Mar +Zone Africa/Maputo 2:10:18 - LMT 1909 2:00 - CAT # Namibia -- 2.44.0