time zone

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World map showing standard time zones, with each zone shaded and labeled by its offset from Greenwich Mean Time. The International Date Line is marked with a bold, zigzagging line in the Pacific Ocean, and variations for half-hour and other non-standard offsets are indicated. Continents, major countries, and oceans are labeled for reference.

Map centered on New York, showing major international flight paths to cities such as London, Rome, Delhi, Sydney, Tokyo, and Honolulu. Arrows indicate the direction of travel, with numbers around the edge representing time zones crossed. A scale at the bottom explains that crossing one time zone equates to approximately one day of jet lag, with days of jet lag increasing as more time zones are crossed.

time zone: References & Edit History

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Article History

Type	Description	Contributor	Date
	Invalidated site: NASA - Time Zones and Universal Time.	Grace Young	Jul 31, 2026
	Add new Web site: Frontiers - Frontiers in Physiology - Daylight Saving Time and Artificial Time Zones A Battle Between Biological and Social Times.	Grace Young	Oct 31, 2025
	Add new Web site: University of Alaska Fairbanks - Geophysical Institute - Time Zones.	Grace Young	Jul 26, 2025
	Add new Web site: CiteSeerX - Longitude matters: time zones and the location of foreign direct investment (PDF).	Yamini Chauhan	Apr 14, 2025
	Add new Web site: BBC News - How time zones confused the world.	Grace Young	Nov 19, 2024
	Add new Web site: IBM Documentation - Time zone.	Grace Young	Jul 31, 2024
	Add new Web site: Exploring Our Fluid Earth - Weird Science: The Prime Meridian and Time Zones.	Gloria Lotha	Feb 03, 2024
	Add new Web site: Geosciences LibreTexts - Time.	Gloria Lotha	Oct 10, 2023
	Added material about the introduction of time zones.	Erik Gregersen	Mar 14, 2022
	Add new Web site: ThoughtCo. - The History of How Time Zones Came to Be.	Gloria Lotha	Sep 24, 2018
	Add new Web site: Easy Science for Kids - Time Zone.	Grace Young	Dec 21, 2016
	Add new Web site: Australia.gov.au - Time.	Grace Young	Jan 21, 2014
	Revised and updated map of world time zones added.	J.E. Luebering	Apr 11, 2012
	Added map of world time zones.	Richard Pallardy	Jun 30, 2010
	Added new Web site: Enchanted Learning - Time Zones: Their Invention and Implementation.	Shiveta Singh	Apr 09, 2009
	Added new Web site: Wolfram Research - Eric Weisstein's World of Astronomy - Time Zone.	Gloria Lotha	May 14, 2008
	Article added to new online database.	The Editors of Encyclopaedia Britannica	Jul 20, 1998