Daylight Saving Time: Turn Clocks Forward

This Sunday, March 10 at 2 a.m., the Eastern Time Zone officially switches from standard time to daylight-saving time, giving us a later sunrise and sunset while depriving us—sadly—of sixty minutes of sleep. 

Remember to set your clocks forward by an hour before you go to bed Saturday (and brew that coffee extra strong the next morning).

Daylight-saving time is also a good time to change the batteries in your smoke detectors and carbon monoxide detectors, and to test the devices to ensure that they are still working properly.

Below is a brief history and explanation of current DST rules, courtesy of the U.S. National Institute of Standards and Technology:

What is daylight saving time?

Daylight-saving time, or DST, is the period of the year when clocks are moved one hour ahead. In the United States, this has the effect of creating more sunlit hours in the evening during months when the weather is the warmest. We advance our clocks ahead one hour at the beginning of DST, and move them back one hour ("spring forward, fall back") when we return to Standard Time (ST). The transition from ST to DST has the effect of moving one hour of daylight from the morning to the evening. The transition from DST to ST effectively moves one hour of daylight from the evening to the morning.

DST was formally introduced in the United States in 1918. Today, most of the country and its territories observe DST. However, DST is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands and the state of Arizona (with the exception of the Navajo Indian Reservation, which does observe DST).

Daylight-saving time and time zones are regulated by the U. S. Department of Transportation, not by NIST. However, as an official timekeeper for the United States, NIST observes all rules regarding DST when it distributes time-of-day information to the public.

What are the current rules for daylight saving time?

The rules for DST changed in 2007 for the first time in more than 20 years. The new changes were enacted by the Energy Policy Act of 2005, which extended the length of DST in the interest of reducing energy consumption. The new rules increased the duration of DST by about one month. DST will now be in effect for 238 days, or about 65% of the year, although Congress retained the right to revert to the prior law should the change prove unpopular or if energy savings are not significant. At present, daylight-saving time in the United States

• begins at 2 a.m. on the second Sunday of March and
• ends at 2 a.m. on the first Sunday of November

In 2013, DST is from 2 a.m. (local time) on March 10 until 2 a.m. (local time) on Nov. 3.