Q:

Why do we change the clocks twice a year?

A:

Quick Answer

The clocks change twice each year to accommodate Daylight Saving Time. In the U.S., this time period begins on the second Sunday in March and ends on the first Sunday in November.

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Why do we change the clocks twice a year?
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Full Answer

Clocks move forward one hour in March and move backward one hour in November. Most people remember the changes with the catch phrase "spring forward, fall back," referring to the season when the changes take place. The U.S. government initially started Daylight Saving Time during World War I to save energy for wartime production. The federal government enacted Daylight Saving Time as a permanent change in 1966. Starting in 2007, the government extended the time period by four weeks as a means to save energy through longer daylight hours.

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Related Questions

  • Q:

    When do we set our clocks back?

    A:

    People in the United States set their clocks back at the end of Daylight Savings Time every year, which usually occurs in October or November. Not all countries in the world use Daylight Saving Time, but many do. It is most popular in the Western Hemisphere.

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  • Q:

    When do we set clocks back an hour?

    A:

    Clocks are set back on the first Sunday of November every year. At 2 a.m., people living in the United States set their clocks back to Standard Time, marking the end of Daylight Saving Time.

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  • Q:

    What day do we turn the clocks back?

    A:

    The date that clocks are turned back for Daylight Savings Time changes each year. In 2015, the day to turn the clocks back is Nov. 1. The day to turn the clocks forward an hour is be March 8, 2015.

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  • Q:

    How do atomic clocks work?

    A:

    Atomic clocks work by exposing an atomic element to radio waves and then measuring the vibration between energy states of the atom's electrons. There are three main types of atomic clocks: cesium, rubidium and hydrogen. A second is defined as 9,192,631,770 cesium vibration cycles.

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