Daylight saving time in Eastern Time

The rule dates from 2007. Section 110 of the Energy Policy Act of 2005 moved the start of daylight time from the first Sunday in April to the second Sunday in March, and the end from the last Sunday in October to the first Sunday in November. Canadian provinces that observe DST use the same dates.

Because each place changes at 2:00 AM on its own clock, the whole Eastern zone switches at one instant; Central, Mountain and Pacific Time follow one, two and three hours later. The live Eastern Time clock shows which offset applies now.

The original argument was fuel: shift an hour of daylight from the early morning, when most people sleep, to the evening, when lamps would burn. Germany introduced DST during the First World War, in 1916, and the United States followed with the Standard Time Act of March 19, 1918 – the law that made the railroads' time zones official. Congress repealed federal DST in 1919, overriding President Wilson's veto.

Year-round "War Time" ran from February 9, 1942 to September 30, 1945. Local choice then produced a patchwork until the Uniform Time Act of 1966 set one national schedule while letting states opt out. During the oil crisis Congress tried year-round DST from January 6, 1974; dark winter mornings turned opinion against it, and standard time returned on October 27, 1974.

The energy case is now thin: the Department of Energy's 2008 study of the 2007 extension found electricity savings of about 0.5% per day during the added weeks, roughly 0.03% of annual use. The history of Eastern Time covers how the zone itself began.

The EU and the UK change on the last Sundays of March and October, everywhere at 01:00 UTC, so London, Paris and Berlin switch at the same moment. The European Parliament voted in 2019 to end the changes, but member states never agreed which time to keep.

South of the equator the seasons are reversed: Sydney and Melbourne use daylight time from the first Sunday in October to the first Sunday in April, so the New York–Sydney gap swings between 14, 15 and 16 hours (see EST to AEST).

Not yet. The Uniform Time Act lets a state stay on standard time all year, as Arizona and Hawaii do, but not adopt year-round daylight time without Congress. So 19 states, Florida among them since 2018, have passed laws that take effect only if federal law changes.

The Sunshine Protection Act would make DST permanent nationwide, with a state opt-out. A version passed the Senate by unanimous consent in March 2022, then died in the House. Reintroduced in 2025, H.R. 139 passed the House on July 14, 2026, by 308 votes to 117. As of late 2026 it sits with the Senate Commerce Committee without a vote; Senator Tom Cotton, who blocked a fast-track attempt in October 2025, argues that dark mornings endanger children at bus stops. Until the Senate acts, the clock changes remain law.

Sleep medicine wants the opposite. The American Academy of Sleep Medicine has backed permanent standard time since 2020 (reaffirmed in 2023), as has the American Medical Association since 2022: morning light anchors the body clock. Under permanent DST the latest winter sunrise would come around 9:00 AM in Detroit and Indianapolis – what sank the 1974 experiment.

Ontario's Time Amendment Act of 2020 would adopt permanent daylight time only if Quebec and New York do; it is not in force. Quebec said on October 28, 2026 that it will table a bill to stop changing clocks, without yet choosing which time to keep.