Daylight saving time in the United States

Daylight saving time in the United States
Harris & Ewing Collection · Public domain · source
Name	Daylight saving time in the United States
Caption	Current U.S. time zones showing DST observance
Utc offset	−04:00 to −10:00 (DST)
Utc offset DST	−03:00 to −09:00 (DST)
Date start	1918
Legislation	Standard Time Act of 1918, Uniform Time Act of 1966

Daylight saving time in the United States is the practice of advancing clocks by one hour during the warmer part of the year, typically from spring to autumn. This system is governed by a complex interplay of federal and state laws, most notably the Uniform Time Act of 1966. While most of the country observes DST, significant exceptions exist, including the states of Arizona and Hawaii, leading to ongoing national debate about its utility and effects.

History

The concept was first proposed in the United States by Benjamin Franklin in a 1784 satirical essay. Serious advocacy began in the early 20th century, notably by William Willett in Britain and Robert Garland in Pittsburgh. The United States first implemented nationwide daylight saving time during World War I under the Standard Time Act of 1918, primarily as a wartime conservation measure, a policy also adopted by many European nations including Germany and the United Kingdom. The law was repealed after the war due to public opposition, leaving time-setting to local option, which created a chaotic patchwork of observance. It was reinstated nationally during World War II by order of President Franklin D. Roosevelt, who instituted year-round "War Time". After the war, the inconsistency returned until the passage of the Uniform Time Act of 1966.

Federal and state law

The current federal framework is established by the Uniform Time Act of 1966, which standardized the start and end dates for DST across the nation. This law was amended by the Emergency Daylight Saving Time Energy Conservation Act of 1973 during the 1973 oil crisis, instituting year-round DST for two years, and later by the Energy Policy Act of 2005, which extended the DST period to its current length. Under federal law, states are not required to observe DST. However, if a state chooses to observe it, it must follow the federally mandated schedule. The power to change time zones or opt out of DST entirely rests with state legislatures, though any time zone change requires approval from the United States Department of Transportation.

Observance and exceptions

Daylight saving time is observed in most of the United States, beginning on the second Sunday in March and ending on the first Sunday in November. The only states that do not observe DST at all are Arizona (except for the Navajo Nation) and Hawaii. Several U.S. territories, including Puerto Rico, Guam, the U.S. Virgin Islands, and American Samoa, also do not observe it. Within observing states, some localities may be in different time zones, such as parts of Indiana which historically exempted themselves until a 2006 state law. The Navajo Nation, which extends into Arizona, does observe DST, creating a unique situation within the non-observing state.

Proposals for change

There have been numerous legislative proposals to alter or eliminate daylight saving time. The Sunshine Protection Act, which has been introduced multiple times in the United States Congress, aims to make DST permanent nationwide, effectively moving standard time forward by one hour year-round. States like Florida, California, and Washington (state) have passed legislation expressing intent to adopt permanent DST, but such changes require federal authorization. Conversely, states like Alabama and Wyoming have passed measures to adopt permanent standard time, which would be allowed under current federal law if they chose to forgo DST entirely. These movements have gained momentum in recent years, prompting hearings in committees like the United States Senate Committee on Commerce, Science, and Transportation.

Effects and controversy

The effects of daylight saving time are widely debated. Proponents, including organizations like the Chamber of Commerce, have historically argued it conserves energy, promotes outdoor retail activity, and reduces traffic accidents. However, studies by agencies like the United States Department of Energy and research from institutions like Stanford University have shown mixed or negligible energy savings. Opponents, including sleep scientists and medical associations, cite significant public health and safety drawbacks, including increased risks of heart attacks, strokes, and workplace injuries following the spring transition. The American Academy of Sleep Medicine advocates for the adoption of permanent standard time, aligning better with human circadian biology. The semi-annual time change also disrupts sectors like agriculture, aviation, and broadcast television, and causes coordination issues with financial markets and international partners like Canada and Mexico.

Category:Daylight saving time Category:Time in the United States