Curious Iowa: Why do we have daylight saving time?

Editor’s note: In 2025, clocks spring forward one hour on March 9. On November 2, 2025 clocks fall back one hour.

Twice a year, whether they detest it or tolerate it, Iowans change their clocks to comply with daylight saving time. In 2024, clocks sprung forward on March 10. This coming Sunday, at 2 a.m. Nov. 3, daylight saving time will end and clocks will “fall back” one hour.

In recent years, both Iowa and U.S. lawmakers have considered establishing permanent daylight saving time, while sleep experts have pushed for permanent standard time.

So why does Iowa still have daylight saving time? That’s what one curious Iowan asked Curious Iowa, a Gazette series that answers readers’ questions about our state and its people.

To answer this question, we looked at arguments for permanent standard time and for permanent daylight saving time, as well as the history of daylight saving time — or “fast time,” as it was once known.

  Buy Photo

Why was daylight saving time adopted?

In March 19, 1918, President Woodrow Wilson signed the Standard Time Act into law. The act established five time zones across the U.S. and adopted daylight saving time, starting March 31.

The thought was that daylight saving time would increase the amount of daylight during the evenings and help save energy costs during World War I. It was repealed in 1919 after the war ended.

  Buy Photo

Leo Landis, state curator for the State Historical Society of Iowa, said that having more daylight in the evenings was attractive because it reduced the amount of coal being burned, and it provided safer environments for women as they walked home from work to contribute to war efforts.

During World War II, the U.S. adopted year-round daylight saving time — known as “war time.” Farmers vehemently opposed it. The Cedar County Farm Bureau said it was “a hindrance rather than a benefit” in meeting farm production goals, The Gazette reported in 1943.

The Iowa Legislature twice adopted resolutions asking Congress to do away with daylight saving time. Those efforts were not successful, and “war time” lasted from February 1942 until September 1945 when the war ended.

Cities differed

Believe it or not, there was a time when cities in Iowa could observe time differently than their neighbors. Some cities adopted daylight saving time, others didn’t. The state had no uniform time.

In 1954, Cedar Rapids decided to experiment with daylight saving time, from June through September. But the change caused so many issues, the city ended the experiment in August.

The same year, on July 30, the Iowa City Council voted unanimously to revert the city to Central Standard Time on Aug. 15. But on Aug. 11, The Gazette reported, the city of University Heights, which is tucked inside Iowa City, decided to remain on fast time until Sept. 15, as originally planned.

When buzz surrounding daylight saving time resurfaced in 1959, Cedar Rapids held out. In 1962, it went to a vote. Cedar Rapids voters rejected daylight saving time, with 53 percent of voters opposed.

But by the end of April 1964, all of Linn County had adopted daylight saving time through Oct. 4.

Throughout all this, issues arose. Would bars be required to close on standard time or DST? Which time should births be recorded in?

On April 30, 1964, The Gazette reported that despite Cedar Rapids observing fast time, both St. Luke’s and Mercy hospitals recorded births in Central Standard Time as a matter of policy.

Other complaints about daylight saving time included that it was difficult to put children to bed while it was still light out, and it was difficult for farmers, who work by the sun, to get to town to do their shopping or make it to evening events.

Uniform time came in 1966

  Buy Photo

On April 14, 1966, President Lyndon B. Johnson signed the Uniform Time Act into law. The law established uniform daylight saving time from the last Sunday in April to the last Sunday in October each year. It also noted that a state could decide to remain on standard time but that had to apply to the entire state.

The U.S. launched a 2-year trial of permanent daylight saving time with the Emergency Daylight Saving Time Energy Conservation Act of 1973, which aimed to save energy during the oil crisis. The experiment started on Jan. 6, 1974, and lasted less than a year.

Landis, the state curator, said he was in elementary school at that time and remembers being told at school to be cautious while walking to the bus stop in the dark.

“There really was the concern about saving energy, but also then the counter to it is child safety,” Landis said. “And I can tell you it was dark waiting for the bus that January and part of February when the energy saving act was in effect.”

Through the years, the dates for the start of daylight saving time have shifted. But the Energy Policy Act of 2005 changed the start and end dates to what is observed today: Daylight saving time starts the second Sunday of March and goes until the first Sunday in November.

In 2008, the U.S. Department of Energy reported to Congress on the energy savings during a period in 2005 in which daylight saving time was extended by four weeks. It found electricity savings were about 0.5 percent each day during the extension, or 0.03 percent of total electricity consumption over the year.

Today, two states do not observe daylight saving time: Hawaii and Arizona, excluding the Navajo Nation.

Who struggles with daylight saving time?

  Buy Photo

Daylight saving time disrupts the body’s circadian rhythm. Dr. Erin Flynn-Evans, a circadian biologist and consultant with the American Academy of Sleep Medicine, said those disruptions come with health consequences.

We know from studies of shift workers that circadian misalignment increases one’s risk for hormone dependent cancers, diabetes, heart disease and other cardiovascular diseases, she said.

On the edge of a time change, she added, it’s difficult to get up in the morning because our bodies want to wake up a little bit after the sun rises.

“So we see more motor vehicle crashes as we’re coming out of daylight saving time, and then as we’re going back into it, so there’s that sort of immediate risk.” Flynn-Evans said. “There’s more medical errors, more people go to the hospital for heart attacks and strokes.”

Time changes are “incredibly disruptive” from the physiological point of view, she said, and some people will be more sensitive to change than others. Those who likely will have more trouble with the upcoming time change, she added, are young children and “people who are morning types.”

“Most of the population likes this time change. About two thirds of the population are more late types than morning types,” Flynn-Evans said. “And so we get an extra hour of sleep, and we sort of realign to a timing of sleep that fits us better relative to our social schedule.”

Flynn-Evans said that morning people should prepare for the time change by maximizing evening light and keeping lighting dim in the morning, even if one is rising early.

“You don’t want to be blasted with bright sunlight first thing or that will just sort of keep you on the time that we’re on now,” Flynn-Evans said.

Who is working to eliminate time changes?

  Buy Photo

There are efforts to eliminate time changes, but the question is whether to make standard time permanent or daylight saving time permanent.

The Coalition for Permanent Standard Time was formed in 2023 by sleep experts with the American Academy of Sleep Medicine.

“Based on all of the evidence, permanent standard time is really the best choice because it better aligns with when our bodies naturally want to sleep and wake,” Flynn-Evans said.

But so far, Congress has only seen bills that would establish permanent daylight saving time.

In 2022, the Sunshine Protection Act of 2021 passed the U.S. Senate. It was reintroduced in 2023 but did not move forward.

In 2022, an Iowa bill similar to the Sunshine Protection Act, HF 2331, passed the Iowa House. In 2024, Iowa House File 498 tried again to advance permanent daylight saving time in Iowa, but it didn’t make it any further than advancing to the House State Government Committee.

Some states already have passed bills like Iowa’s two bills, but changes on a state level are contingent on the Uniform Time Act of 1966 being repealed, or if surrounding states also make the switch.

So until Congress makes a big move, Iowans will continue to observe daylight saving time, whether they like it or not.

Have a question for Curious Iowa?

Tell us what to investigate next.

Recommended Reading

Enter to win tickets to Festival of Trees

Comments: bailey.cichon@thegazette.com