Girish Mahajan (Editor)

Time in Indonesia

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Time in Indonesia

The Indonesian archipelago geographically stretches across four time zones from UTC+6 in Aceh to UTC+9 in Western Papua. However, The Indonesian government only recognizes three time zones in its territory:

Contents

  • Indonesia Western Time—seven hours in advance (UTC+7) of Greenwich Mean Time (GMT)
  • Indonesia Central Time— eight hours ahead (UTC+8) of GMT; and
  • Indonesia Eastern Time—nine hours ahead (UTC+9) of GMT

    • The boundary between the western and central time zones established is a line running north between Java and Bali through the center of Kalimantan. The border between central and eastern time zones runs north from the eastern tip of Timor to the eastern tip of Sulawesi.

    Daylight saving time is not currently observed in almost all of Indonesia due to its tropical location, resulting in those areas using their respective time zone all year long. The only unofficial exception of this is Muara Teweh and Maurainu, which unofficially uses Western Indonesian Daylight Time.

    Current usage

    In Indonesia, the keeping of standard time is divided into three time zones:

    Indonesia Western Standard Time

    Indonesia Western Standard Time (IWST) (WIB, Indonesian: Waktu Indonesia Barat) (UTC+07:00) is observed in:

  • All provinces in the island of Sumatra and its surrounding islands including major cities such as: Banda Aceh, Medan, Padang, Pekanbaru, Palembang, Jambi, Batam and Bandar Lampung.
  • All provinces in the island of Java including major cities such as: Bandung, Surabaya, Jakarta, Semarang and Yogyakarta.
  • Two provinces in Kalimantan island: West Kalimantan and Central Kalimantan. Including major cities such as: Pontianak, Palangkaraya, and Sampit. Muara Teweh and Maurainu unofficially uses Western Indonesian Daylight Time, which has the same time as Central Indonesian Time.

    • IANA time zone database identifiers are "Asia/Jakarta" and "Asia/Pontianak"

    Indonesia Central Standard Time

    Indonesia Central Standard Time (ICST) (WITA, Indonesian: Waktu Indonesia Tengah) (UTC+08:00) is observed in:

  • All provinces in the island of Sulawesi including major cities such as: Makassar, Manado, Palu and Gorontalo.
  • All provinces in the Lesser Sunda Islands including major cities such as: Denpasar, Mataram, and Kupang.
  • Three provinces in Kalimantan island: North Kalimantan, East Kalimantan and South Kalimantan, including major cities such as: Balikpapan, Banjarmasin, Samarinda, and Tarakan.

    • IANA time zone database identifier is "Asia/Makassar"

    Indonesia Eastern Standard Time

    Indonesia Eastern Standard Time (IEST) (WIT, Indonesian: Waktu Indonesia Timur) (UTC+09:00) is observed in:

  • Maluku Islands including major cities such as: Ambon City, Ternate City, and Tidore.
  • All provinces in West Papua including major cities such as: Jayapura, Biak, and Merauke.
  • All provinces in Papua including all major islands in the province.

    • IANA time zone database identifier is "Asia/Jayapura"

    It observed since January 1, 1988 (based Keputusan Presiden No. 41 tahun 1987). Before it, Western and Central Kalimantan used ICST, and Bali used IWST from January 1, 1964 (based Keputusan Presiden No. 243 tahun 1963)

    Historical usage

    During the colonial era until early independence, the time in Indonesia (Dutch East Indies) was regulated as follows:

    Standarization Time Zone Indonesia 1932

  • Northern Sumatra Time (NST) (UTC+06:30), was observed in Aceh, Padang and Medan.
  • Central and Southern Sumatra Time (CSST) (UTC+07:00), was observed in Bengkulu, Palembang and Lampung.
  • Java, Bali, and Borneo Time (JBBT) (UTC+07:30), was observed in Java (Jawa), Bali, Madura and Kalimantan.
  • Celebes Time (CBT) (UTC+08:00), was observed in Sulawesi and Lesser Sunda Islands.
  • Moluccan Time (MCT) (UTC+08:30), was observed in Ternate, Namlea, Ambon, Sofifi and Banda.
  • West Irian Time (WIT) (UTC+09:00) was observed in West Irian. It observed during November 1, 1932 to August 31, 1944.
  • Dutch New Guinea Time (DGT) (UTC+09:30), was observed in West Irian during named Dutch New Guinea because Netherlands still hold West Irian. It observed from September 1, 1944 to December 31, 1963.

    • Daylight saving time was observed in Jakarta from May 1, 1948 to May 1, 1950. It's UTC offset during daylight saving time is UTC+08:00.

    It observed from November 1, 1932 to March 22, 1942, and from September 23, 1945 to December 31, 1963, except West Irian, ever observed it until 1944 and Jakarta, ever observed it all, except from May 1, 1948 to May 1, 1950.

    From March 23, 1942 to September 22, 1945, All region in Indonesia, except West Irian used Japan Standard Time (JST) (UTC+09:00) for the sake of the effectiveness of military operations Japan in Indonesia

    IANA time zone database

    The IANA time zone database contains four zones for Indonesia in the file zone.tab.

  • Asia/Jakarta
  • Asia/Pontianak
  • Asia/Makassar
  • Asia/Jayapura

    • References

    Time in Indonesia Wikipedia
    (Text) CC BY-SA