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# Standards: Daylight Saving Time (DST)
- URL: https://www.foodconsumer.org/daylight_saving_time_1103110732/
- Published: 2011-11-03T21:31:00.000Z
- Updated: 2026-09-22T16:14:59.000Z
- Description: Most of the US turns clocks back an hour at 2 a.m. local time, but Hawaii, most of Arizona and several territories skip it. The 2005 Energy Policy Act moved Daylight Saving Time to the second Sunday in March through the first Sunday in November. About 70 countries observe it.
- Author: Food Consumer
- Tags: Environment, Health News, #vivvo-import

Most people in the U.S. will turn their clocks back one hour at 2 AM local time on Sunday, Nov. 6\. But Hawaii, most of Arizona, and some U.S. territories do not observe Daylight Saving Time

[Daylight Saving Time (DST)](http://aa.usno.navy.mil/faq/docs/daylight%5Ftime.php?ref=foodconsumer.org) is a widely used system that adjusts the official local time forward from the[official standard time](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9704&ref=foodconsumer.org) during summer months, usually by one hour.

The [Energy Policy Act of 2005](http://thomas.loc.gov/cgi-bin/bdquery/z?d109:H.R.6:&ref=foodconsumer.org) changed the start and end dates of Daylight Saving Time in the United States. As of 2007, DST begins on the second Sunday in March and ends on the first Sunday in November. The [U.S. Department of Energy (DOE)](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=10716&ref=foodconsumer.org) is studying the impact of this DST extension, and the[U.S. Congress](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=12023&ref=foodconsumer.org) retains the right to revert to the previous DST schedule if the study shows it does not produce a significant savings of energy.

Use of Daylight Saving Time in the United States, is governed by the Uniform Time Act of 1966\. This Act provides a standard for establishing the dates when DST begins and ends in the U.S., while allowing local exemptions from its observance. States wishing to be exempt from DST may pass a law exempting the entire state. The states of [Arizona](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9837&ref=foodconsumer.org) and [Hawaii](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9853&ref=foodconsumer.org) do not observe DST. However, the Navajo Indian Reservation in Arizona does. In addition, [American Samoa](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9840&ref=foodconsumer.org), [Guam](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9852&ref=foodconsumer.org), the [Northern Mariana Islands](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9881&ref=foodconsumer.org), [Puerto Rico](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9886&ref=foodconsumer.org), and the [U.S. Virgin Islands](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=9897&ref=foodconsumer.org) do not observe DST.

Approximately [70 countries observe DST](http://www.webexhibits.org/daylightsaving/g.html?ref=foodconsumer.org).

**Additional Resources:**

- [Daylight Saving Time Rules](http://www.nist.gov/pml/div688/dst.cfm?ref=foodconsumer.org)
- [Time Exhibits](http://www.time.gov/exhibits.html?ref=foodconsumer.org)
- [The Seasons: Spring, Summer, Fall and Winter](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=10512&ref=foodconsumer.org)
- [Standards: Leap Year](http://answers.usa.gov/system/selfservice.controller?CONFIGURATION=1000&PARTITION%5FID=1&CMD=VIEW%5FARTICLE&USERTYPE=1&LANGUAGE=en&COUNTRY=US&ARTICLE%5FID=10649&ref=foodconsumer.org)

by USA.gov team