Clocks fell back an hour Sunday. Here's when daylight saving time returns, and who skips it

SAN JOSE - Daylight saving time ended at 2 a.m. Sunday, Nov. 1, when clocks in California and most of the country went back one hour to 1 a.m.  That made Sunday a 25-hour day, with the 1 a.m. hour happening twice, according to the National Institute of Standards and Technology (NIST), the federal lab that keeps the nation's official time.

The switch moves an hour of daylight from the evening to the morning, NIST says.  Until March, sunrise and sunset will both come an hour earlier by the clock than they would under daylight saving time, as the Legislative Analyst's Office explains.

Phones and computers that get their time from the internet should change on their own.  NIST says the time signals it sends out are in Coordinated Universal Time, the world's reference time, and a device's operating system handles the local time zone and daylight saving time, so it is important to keep software updated.

When it comes back

Under federal law, daylight saving time begins at 2 a.m. on the second Sunday of March and ends at 2 a.m. on the first Sunday of November.  That means clocks will "spring forward" again at 2 a.m. on Sunday, March 14, 2027, jumping straight to 3 a.m., a day with only 23 hours.  Daylight saving time will then last until Sunday, Nov. 7, 2027.

NIST says daylight saving time now covers 238 days, or about 65% of the year.  It has run on this schedule since 2007, after Congress passed the Energy Policy Act of 2005 to save energy and lengthened it by about a month.  Before that, it ran from the first Sunday in April to the last Sunday in October, according to the federal law's history notes.

Who skips it

Not everyone changes their clocks.  Daylight saving time is not observed in Hawaii or in most of Arizona, NIST says.  The exception in Arizona is the Navajo Nation's reservation, which does change its clocks.

Five U.S. territories also stay on standard time all year: Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa and the Northern Mariana Islands.  Guam and the Northern Mariana Islands share their own time zone, called Chamorro standard time, which Congress created in 2000.

States have that choice because of the Uniform Time Act of 1966, the federal law that sets the dates.  A state may exempt itself and stay on standard time all year, but it cannot set its own switch dates.  Federal law also does not let a state stay on daylight saving time all year, according to the Legislative Analyst's Office, the California Legislature's nonpartisan budget and policy adviser.  The U.S. Department of Transportation, not NIST, regulates daylight saving time and time zones.

A century of changing clocks

Daylight saving time first came to the United States in 1918, NIST says.  A photo from that year in the Library of Congress shows the Senate's sergeant at arms moving the hands of the Ohio Clock in the U.S. Capitol forward for the first daylight saving time while three senators look on.

California's stalled push

California voters first approved daylight saving time in a 1949 ballot measure, the Legislative Analyst's Office says.  Because voters put it in place, lawmakers could not change it without going back to the ballot.

In November 2018, voters passed Proposition 7, which lets the Legislature change daylight saving time with a two-thirds vote, as long as federal law allows it.  It won 59.7% of the vote statewide, and 58.8% in Santa Clara County, according to the California Secretary of State.

The next month, Assembly members Chu, Gonzalez and Obernolte introduced Assembly Bill 7, which would have put California on daylight saving time all year once the federal government allowed it.  The bill passed the Assembly 72-0 in May 2019.  In the Senate, its first committee hearing was canceled at the author's request, and the bill died there in November 2020, according to the Legislature's bill records.

So for now, California keeps changing its clocks twice a year, like most of the country.

Source:  NIST daylight saving time rules, 15 U.S.C. 260a, Cornell Law School Legal Information Institute, Public Law 106-564, Chamorro time zone, Northern Mariana Islands Code, 1 CMC 502, Legislative Analyst's Office on Proposition 7 (2018), California Secretary of State, 2018 ballot measure results, AB 7 (2019) bill text and AB 7 bill status.