A Brief History of Daylight Saving Time in the U.S.

Daylight saving time isn’t actually that old. The first serious proposal came from George Hudson, a New Zealand entomologist, in 1895 — he wanted more daylight after work to chase insects. Benjamin Franklin’s famous 1784 satire about Parisians sleeping through morning sunlight is sometimes cited as the origin, but it was a joke about the value of candles.

World War I

Germany was the first country to actually implement DST, in April 1916, to conserve coal during the war. The U.S. followed in March 1918 with the Standard Time Act, which both established the standard time zones (Eastern, Central, Mountain, Pacific) and introduced DST. After the war ended, DST was so unpopular among farmers that Congress repealed the federal mandate in 1919 — though many cities kept it.

The patchwork era (1920–1966)

For 47 years, DST in the U.S. was a free-for-all. Cities, counties and states could each decide whether and when to observe DST. By the early 1960s, a single Greyhound bus ride from Steubenville, Ohio to Moundsville, West Virginia (about 35 miles) crossed seven time changes.

The Uniform Time Act (1966)

To end the chaos, Congress passed the Uniform Time Act of 1966, which:

• Set DST to begin on the last Sunday in April and end on the last Sunday in October.
• Required states to observe DST uniformly across their entire territory (or opt out entirely).
• Created the modern CDT/CST/EDT/EST naming convention.

Recent changes

The Energy Policy Act of 2005 extended DST by about a month, moving the start to the second Sunday in March and the end to the first Sunday in November (in effect since 2007). That’s still the rule today.

In 2022 the U.S. Senate passed the Sunshine Protection Act, which would have made DST permanent year-round (so we’d always be in CDT/EDT/etc.), but the House never voted on it. Permanent DST remains a perennial debate.

Who opts out?

Two U.S. states do not observe DST: Hawaii and most of Arizona. The Navajo Nation in northeast Arizona does observe DST, creating a confusing patchwork inside the state. Several U.S. territories also skip DST: Puerto Rico, U.S. Virgin Islands, American Samoa, Guam and the Northern Mariana Islands.

TL;DR

CDT exists because Congress, in 1966 and again in 2005, decided the U.S. should have a unified summer DST. Today CDT runs from the second Sunday in March through the first Sunday in November every year — until politicians change the rules again.