Which country first adopted daylight saving time?

Germany was the first country to adopt daylight saving time nationwide. The German Empire advanced clocks by one hour on April 30, 1916, during World War I.

The policy was introduced largely to conserve coal and reduce the need for artificial lighting during wartime. Austria-Hungary followed soon afterward, and the idea spread rapidly across Europe. The United Kingdom, France, and the United States adopted daylight saving time later.

A common mix-up involves Port Arthur and Fort William in Ontario, Canada, which introduced a seasonal clock change locally in 1908. That makes Canada an early pioneer, but Germany is generally credited as the first country to implement daylight saving time across its territory.

Germany later discontinued the practice after the war, restored it during World War II, and permanently reintroduced modern daylight saving time in 1980. Today, the policy remains common in Europe, although many countries worldwide do not observe it.