Standard Time Act of 1918

Standard Time Act

Long title	An Act to save daylight and to provide standard time for the United States.
Nicknames	Calder Act Standard Time Act of 1918
Enacted by	the 65th United States Congress
Effective	March 19, 1918
Citations
Public law	65-106
Statutes at Large	40 Stat. 450
Legislative history
Introduced in the Senate as S. 1854 by William M. Calder (R-NY) Passed the House on March 15, 1918 (253-40) Signed into law by President Woodrow Wilson on March 19, 1918

The Standard Time Act of 1918, also known as the Calder Act, was the first United States federal law implementing Standard time and Daylight saving time in the United States. It authorized the Interstate Commerce Commission to define 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The section concerning daylight saving time was repealed by the act titled An Act For the repeal of the daylight-saving law, Pub.L. 66–40, 41 Stat. 280, enacted August 20, 1919, over President Woodrow Wilson's veto.

Section 264 of the act mistakenly placed most of the state of Idaho (south of Salmon River (Idaho)) in UTC−06:00 CST Central Standard Time, but was amended in 2007 by Congress to UTC−07:00 MST Mountain Standard Time. MST was observed prior to the correction.

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