Daylight saving time (aka daylight time, aka DST) has its origins in the United States with the Standard Time Act of 1918 (See Pub.L. 65-106, United States Statutes at Large, 65^th Congress), an effort to conserve fuel during the First World War. With the Uniform Time Act of 1966, the starting and ending dates were standardized for every area in the United States observing daylight saving time (Pub.L. 89-387, Unites States Statutes at Large, 89^th Congress).

Throughout the years the start and end dates for daylight time have changed and changed again (and were even briefly instituted year-round); wartime and the 1970s energy crisis were the leading causes for daylight time’s evolving history. Starting in 2007, after the Energy Policy Act of 2005, DST begins the second Sunday in March and ends the first Sunday in November.

This Sunday, November 2, marks this year’s end of daylight saving time, when at 2:00 a.m. the clocks are turned back to 1:00 a.m. (Unless you’re in Hawaii, or one of the territories, or one of the areas of Arizona that stick with Standard Time year-round. Indiana, which straddles two time zones and didn’t recognize daylight saving time until 2006, used to be particularly confusing.)

For more information on DST, check out the National Institute of Standards and Technology (NIST), a division of the U.S. Department of Commerce, and their FAQs on daylight saving time. You can also read the current United States Code (Title 15, Chapter 6, Subchapter IX – Standard Time) to see how the law stands now.

If you’re really confused – just check here.