Time in Portugal

Time in Europe:
light blue Western European Time / Greenwich Mean Time (UTC)
blue Western European Time / Greenwich Mean Time (UTC)
Western European Summer Time (UTC+1)
red Central European Time (UTC+1)
Central European Summer Time (UTC+2)
yellow Eastern European Time / Kaliningrad Time (UTC+2)
golden Eastern European Time (UTC+2)
Eastern European Summer Time (UTC+3)
light green Further-eastern European Time (UTC+3)
Light colours indicate where standard time is observed all year; dark colours indicate where a summer time is observed.

Portugal has two time zones and observes daylight saving time. Continental Portugal and Madeira use UTC+00:00, while the Azores use UTC–01:00. Daylight saving time (locally known as Hora de Verão, meaning 'summer time') is observed nationwide from the last Sunday in March to the last Sunday in October, so that every year, continental Portugal and Madeira temporarily use UTC+01:00, and the Azores temporarily use UTC+00:00.[1]

History

In the early 19th century, Portugal adopted mean solar time.[2] Navy (located in Lisbon) and Coimbra Astronomical Observatories calculated solar time to be used as legal time in their longitude regions.[2] In 1861, the Astronomical Observatory of Lisbon was founded and, in 1878, it was tasked with the exclusive competence of calculate its mean solar time and to transmit it to rest of the country’s public services.[2] Thus, in practice, Portuguese standard time was defined as the mean solar time at Lisbon Observatory longitude, which was later calculated as being GMT–00:36:44.[3]

In 1911, it was agreed that standard time in Portugal should be defined in accordance with the 1884 prime meridian system.[4] By the Decree of 26 May 1911, a reform was approved regarding standard time in Portugal and in its overseas Empire: although almost all continental Portugal is located west of the 7.5°W meridian (i.e. in the theoretical zone of GMT–01:00 time zone), for mainland Portugal it was adopted GMT+00:00 as its time zone.[4] By the same law, GMT–02:00 time zone was adopted for the Azores and Cape Verde, GMT–01:00 for Madeira and Portuguese Guinea, GMT for São Tomé and Príncipe and São João Baptista de Ajudá, GMT+01:00 for Angola, GMT+02:00 for Mozambique, GMT+05:00 for Portuguese India and GMT+08:00 for Macau and Portuguese Timor.[4] These time zones were adopted on 1 January 1912.[4]

Daylight saving time (Hora de Verão, in Portuguese) was observed for the first time in 1916, during World War I, and it consisted in advancing clocks by 1 hour.[2][3][5] In that year, DST was observed from 17 June to 1 November but in following years until 1921, it was observed from 1 June to 14 October.[2][3]

DST continued to be observed every year in 1920s and 1930s, although some small interruptions had occurred (1922–1923, 1925, 1930 and 1933), as well as DST’s start and end dates which were often changed.[3]

In the years 1942–1945, during World War II, Portugal, not only advanced clocks by 1 hour during DST, as also advanced them by another 1 hour during some months of those years, coming to have clocks 2 hours ahead of GMT, during that “double DST”.[3] Situation returned to normality after 1945, with the end of World War II, and normal DST continued to be observed.[3] In 1948, it was approved that DST should be observed from the first Sunday in April to the first Sunday in October.[6]

From 1966 on, DST started to be observed year-round, so that, in practice, Portugal changed its time zone from WET (GMT+00:00) to CET (GMT+01:00).[3][7] However, due to the later sunrises and sunsets, many complaints accumulated: on winter mornings, people went to work under a completely dark sky and at 9:00, when school classes started, the sun was still rising, which eventually had repercussions on students’ school performance and their safety during morning trips from home to school.[8] Furthermore, in the 1970s, the idea of reintroducing DST as an energy saving measure gained strength in Europe as well as in Portugal.[9] However, although there were so many complaints in the country with the use of GMT+01:00 year round, it became clear to policymakers that if DST was introduced, it could never be observed as CEST (GMT+02:00), and the only solution was to re-adopt WET as standard time. So, in 1976, Portugal adopted WET (GMT+00:00) as its standard time.[8] DST started to be observed every year as WEST (GMT+01:00) usually from early April to later September.[3][8] From 1981 on, DST started to be observed from the last Sunday in March to the last Sunday in September.[3]

In 1986, time in Portugal began to be calculated in accordance with UTC, instead of GMT.[2][10]

In 1992, during Cavaco Silva government, by Decree-Law 124/92, mainland Portugal officially changed its time zone from WET (UTC+00:00) to CET (UTC+01:00).[3][11] CEST (UTC+02:00) began to be observed as DST, from the last Sunday in March to the last Sunday in September.[3][11] The measure, approved without the consultation of Lisbon Observatory, had the intention of promoting energy savings, in order that “Portugal follow, in work schedules, the countries with which it maintains more frequent contacts” (DL 124/92) and so promoting economic growth.[11] However, the measure quickly proved to be a failure in achieving its objectives and become unpopular: as in the 1967–1976 period, on winter mornings, the sun was still rising at 9:00, and people went to work in the dark.[12][13] Obviously, children also began the school day in darkness, with repercussions on their standards of learning, school performance and sleep habits.[13][14][15] It was even common that children fall asleep on the early morning classes.[12][15] On summer evenings, the usage of CET and CEST was revealed to have a disturbing effect on people’s sleep habits, particularly children's, as the sun was still setting at 22:00 or 22:30, so the sky was only completely dark towards midnight.[12][15][14] A company hired by European Commission conducted a study which concluded that, in fact, there were no energy savings because in the early morning, due to the dark, workers turned on lights in their offices, and they forgot to turn them off, leaving them switched on for the rest of the morning, which increased energy consumption.[13][15] Concerns also emerged concerns about the effect of the coincidence of rush hours with the hottest hours of the day on air pollution.[13][16] Furthermore, an increase in the number of assaults on children in the morning was observed, and insurance companies reported a rise in the number of accidents.[12][17] Due to all of these concerns and complaints, it became clear that situation could not continue much longer without a new analysis. In December 1995, the government (now led by António Guterres) commissioned a report to Lisbon Observatory on the issue of Portuguese standard time.[18] In February 1996, the Observatory report was released and it concluded that due to the geographical position of Portugal, the country should adopt WET (UTC+00:00) as its time zone, position that the policymakers decided to follow.[16][19]

In 1996, new legislation was approved. By Decree-Law 17/96, mainland Portugal returned to the WET (UTC+00:00) time zone.[3][16] DST would continue to be observed as WEST (UTC+01:00) from the last Sunday in March to the last Sunday in October, thus adopting EU rules regarding DST.[2][3][16] In the same year, Azores and Madeira regional parliaments also approved regional laws who adopted EU rules to their time zones, thus making that DST started to be observed from the last Sunday in March to last Sunday in October in the whole country.[20][21][22]

Date and time notation

In 1996 Portugal adopted ISO 8601 via EN 28601 as NP EN 28601:1996.[23]

Time signalling

The Astronomical Observatory of Lisbon publishes the official time via the Network Time Protocol (NTP), e.g. via "ntp02.oal.ul.pt" and "ntp04.oal.ul.pt".[24]

IANA time zone database

The IANA time zone database contains 3 zones for Portugal. Columns marked with * are from the file zone.tab from the database.

c.c.* coordinates* TZ* comments* UTC offset DST Notes
PT +3843-00908 Europe/Lisbon mainland +00:00 +01:00
PT +3238-01654 Atlantic/Madeira Madeira Islands +00:00 +01:00
PT +3744-02540 Atlantic/Azores Azores −01:00 +00:00

References

  1. ↑ Time and Date: Western European Summer Time
  2. 1 2 3 4 5 6 7 History of time in Portugal (Astronomical Observatory of Lisbon) (in Portuguese). Retrieved 12 May 2013.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 Time in continental Portugal since 1911 (Astronomical Observatory of Lisbon) (in Portuguese). Retrieved 14 May 2013.
  4. 1 2 3 4 Decree of 26 May 1911 (in Portuguese). Retrieved 12 May 2013.
  5. ↑ Decree 2433, 9 June 1916 (in Portuguese). Retrieved 12 May 2013.
  6. ↑ Decree-Law 37048, 7 September 1948 (in Portuguese). Retrieved 19 May 2013.
  7. ↑ Decree-Law 47233, 1 October 1966 (in Portuguese). Retrieved 12 May 2013.
  8. 1 2 3 Decree-Law 309/76, 27 April 1976 (in Portuguese). Retrieved 12 May 2013.
  9. ↑ Decree-Law 44-B/86, 7 March 1986 (in Portuguese). Retrieved 19 May 2013.
  10. 1 2 3 Decree-Law 124/92, 2 July 1992 (in Portuguese). Retrieved 12 May 2013.
  11. 1 2 3 4 Assembly of the Republic – session of 8 February 1996 Diário da Assembleia da República (I Series) (in Portuguese), 7th Parliament of the 3rd Portuguese Republic (1995–1999), 1st Legislative Session (1995–1996), p. 1056, 9 February 1996. Retrieved 15 May 2013.
  12. 1 2 3 4 Raposo, Pedro (March 2006), Com as horas trocadas, O Observatório (in Portuguese), vol. 12, nr. 3, p. 5, Lisbon, Portugal, Astronomical Observatory of Lisbon. Retrieved 26 May 2013.
  13. 1 2 Fuso horário ainda divide opiniões (in Portuguese), Oporto, Portugal, Jornal de Notícias (24 October 2009). Retrieved 14 May 2013.
  14. 1 2 3 4 Segurar as rédeas do tempo tem muito que se lhe diga (in Portuguese), Lisbon, Portugal, Público (24 October 2009) (only for subscribers) (copy of the notice find in the following personal websites As Palavras dos Outros, Geopedrados). Retrieved 21 May 2013
  15. 1 2 3 4 Decree-Law 17/96, 8 March 1996 (in Portuguese). Retrieved 12 May 2013.
  16. ↑ "Lighter Evenings (Experiment) Bill [HL]".. Retrieved 26 May 2013.
  17. ↑ Comunicado do Conselho de Ministros, 21 de Dezembro de 1995 (in Portuguese), Presidency of the Council of Ministers (21 December 1995), Arquivo da Web Portuguesa. Retrieved 21 May 2013.
  18. ↑ Hora de Verão: Relógios em Portugal adiantam 60 minutos dia 30 (in Portuguese), Lisbon, Portugal, Agência Lusa (12 March 1997), Arquivo da Web Portuguesa. Retrieved 21 May 2013.
  19. ↑ Legislation on time in Portugal (Astronomical Observatory of Lisbon) (in Portuguese). Retrieved 12 May 2013.
  20. ↑ Regional Legislative Decree 6/96/M (Madeira), 25 June 1996 (in Portuguese). Retrieved 26 May 2013.
  21. ↑ Regional Legislative Decree 16/96/A (Azores), 1 August 1996 (in Portuguese). Retrieved 26 May 2013.
  22. ↑ http://www.ipq.pt/backfiles/DN_201002.pdf
  23. ↑ http://www.oal.ul.pt/index.php?link=acerto

Further reading

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