The Standard Time Act of 1918, also known as the Calder Act, was the first

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

federal law implementing

Standard time Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than a local mean time standard. Generally, standard time agrees with the local mean time at some meridian that passes through the r ...

and

Daylight saving time in the United States Most of the United States observes daylight saving time (DST), the practice of setting the clock forward by one hour when there is longer daylight during the day, so that evenings have more daylight and mornings have less. Exceptions include Ar ...

. It defined five time zones for the

continental United States The contiguous United States, also known as the U.S. mainland, officially referred to as the conterminous United States, consists of the 48 adjoining U.S. states and the District of Columbia of the United States in central North America. The te ...

and authorized the

Interstate Commerce Commission The Interstate Commerce Commission (ICC) was a regulatory agency in the United States created by the Interstate Commerce Act of 1887. The agency's original purpose was to regulate railroads (and later Trucking industry in the United States, truc ...

to define the limits of each time zone. The section concerning daylight saving time was repealed by the act titled ''An Act For the repeal of the daylight-saving law'', , over President

Woodrow Wilson Thomas Woodrow Wilson (December 28, 1856February 3, 1924) was the 28th president of the United States, serving from 1913 to 1921. He was the only History of the Democratic Party (United States), Democrat to serve as president during the Prog ...

's veto. As a result of a 1966 amendment of Section 261 to add more time zones, the wording in Section 264 of the act wrongly placed most of the state of

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

(south of the Salmon River) in UTC−06:00 CST (

Central Standard Time The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, and a few Caribbean Islands, Caribbean islands. In parts of that zone (20 states in the US, three provinces or territorie ...

), but was amended in 2007 by Congress to UTC−07:00 MST (

Mountain Standard Time The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time (UTC) when standard time ( UTC−07:00) is in effect, and by subtracting six hours during daylight saving time ( UTC−06:00). The clo ...

). MST was observed prior to the correction.

References

Time in the United States Daylight saving time in the United States 65th United States Congress 1918 in American law {{US-law-stub

See also

References