IDL

Units & Measurements abbreviation · Time Zone

IDL
Stands forInternational Date Line
CategoriesUnits & Measurements

IDL stands for International Date Line, a time zone abbreviation.

An imaginary line roughly following the 180° meridian through the Pacific Ocean, where the calendar date changes by one day. Crossing it westward adds a day, and crossing eastward subtracts one.

Example: Our flight crosses the IDL, so we leave Los Angeles on Tuesday night and land in Sydney on Thursday morning.

Usage notes

The line zigzags to keep island nations on a single date: Kiribati moved it in 1995 so that its eastern Line Islands sit at UTC+14, the earliest time on Earth, and Samoa jumped to the western side at the end of 2011, skipping December 30 entirely. Unlike the prime meridian, the date line is not fixed by any international treaty.

More time zone abbreviations

  • ET – Eastern Time
  • GMT – Greenwich Mean Time
  • GST – Gulf Standard Time
  • HKT – Hong Kong Time
  • HST – Hawaii-Aleutian Standard Time
  • ICT – Indochina Time
  • IRST – Iran Standard Time
  • IST – India Standard Time
  • JST – Japan Standard Time
  • KST – Korea Standard Time
  • LMT – Local mean time
  • LT – Local time

See all 64 time zone abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.