Soon Illinois will officially “spring forward” from standard time to daylight saving time, marking the first of two clock changes set for 2025.
The final month of meteorological winter comes to a close this week, and while it will certainly feel like spring temperatures, it will soon begin to look like too as sunrise and sunset times adjust.
Here’s what to know about daylight saving time:
When is daylight saving time?
While the United States is currently in standard time, much of the country will switch to daylight time beginning on March 9.
In the U.S., daylight saving time lasts for a total of 34 weeks, typically running from early-to-mid March to the beginning of November in states that observe it.
That means it will remain in effect through the first Sunday of November in most of the U.S.
The clocks were last changed Nov. 3 at the end of daylight saving in 2024, “falling back” an hour. For 2025, clocks will “fall back” again on Nov. 2.
Which states don’t observe daylight saving time?
Nearly every U.S. state observes daylight saving time, with the exceptions of Arizona (although some Native American tribes do observe DST in their territories) and Hawaii. U.S. territories, including Puerto Rico, American Samoa, Guam and the U.S. Virgin Islands, do not observe daylight saving time.
Will President Trump end daylight saving time?
In a December 2024 post on TruthSocial, President Donald Trump, who was president-elect at the time, wrote, “The Republican Party will use its best efforts to eliminate Daylight Saving Time, which has a small but strong constituency, but shouldn’t! Daylight Saving Time is inconvenient, and very costly to our Nation.”
While President Trump’s position seemed to garner an endorsement from advisers Elon Musk and Vivek Ramaswamy, the president-elect’s son, Donald Trump Jr., appeared to back the opposite position.
The younger Trump’s position is consistent with a bill the Senate passed in 2022 that would have made daylight savings time permanent beginning the following year.
Some federal lawmakers have spearheaded efforts to end the time change altogether, saying such a move provides health benefits, gives the economy a boost and allows Americans to enjoy sunlight during their most productive hours.
In 2022, the U.S. Senate passed the Sunshine Protection Act, ending the twice-yearly clock change and making daylight saving time a year-round standard. However, the bill wasn’t considered by House lawmakers, who prioritized other legislation instead.
Almost all states have considered legislation to stay on standard or daylight saving time, and 20 states have passed bills or resolutions to implement year-round daylight saving time in the last several years, according to the National Conference of State Legislatures. But, because federal law currently does not allow for year-round daylight saving time, the states would have to wait for Congress to pass the bill in order to make the switch.
Earlier this month, several members of the Texas House and Senate filed legislation meant to put an end to the seasonal tradition.
Most of the bills filed aim to adopt daylight saving time year-round, an effort that was pushed during the 2023 legislative session, however, state Sen. Judith Zaffirini, D-Laredo, is trying a different approach. Her bill would adopt standard time year-round in Texas, the only option allowed under federal law.
If her legislation becomes law and if Congress ever allows states to observe daylight saving time year-round, voters would get to choose a preference between year-round standard time or daylight saving time.
The Uniform Time Act allows states to exempt themselves from daylight saving time and stay on standard time the entire year. If they do observe daylight saving time, it must begin and end on federally mandated dates.
Why was daylight saving time created?
Daylight savings time was first instated in the U.S. more than a century ago, though some people credit its invention to an essay written by Benjamin Franklin in 1784.
In an essay about saving candles, Franklin wrote “Early to bed, early to rise makes a man healthy, wealthy and wise.” But that was meant more as satire than a serious consideration.
Germany was the first to adopt daylight saving time on May 1, 1916, during World War I as a way to conserve fuel. The rest of Europe followed soon after.
Two years later, the U.S. adopted daylight saving time in March of 1918, with the intention of adding additional daylight hours also as a way to help save energy costs during World War I, according to the U.S. Department of Defense. However, it was unpopular and abolished after World War I.
On Feb. 9, 1942, Franklin Roosevelt instituted a year-round daylight saving time, which he called “wartime.” The law, was again meant to instate daylight saving time to “help conserve fuel and promote national security defense,” the department said. This lasted until Sept. 30, 1945.
Daylight saving time didn’t become standard in the U.S. until the passage of the Uniform Time Act of 1966, which mandated standard time across the country within established time zones. It stated that clocks would advance one hour at 2 a.m. on the last Sunday in April and turn back one hour at 2 a.m. on the last Sunday in October.
The standard schedule for daylight saving changed in 2005, thanks in part to the prevalence of trick-or-treating on Halloween.
Under the conditions of the Energy Policy Act of 2005, daylight saving time starts on the second Sunday in March and ends on the first Sunday in November – a change put in place in part to allow children to trick-or-treat in more daylight.
How would eliminating DST impact the Chicago area?
During standard time, people in the central time zone in the U.S. are aligned perfectly with solar time, but during daylight saving time, they are pushed further away from that clock.
As daylight saving time is observed in Illinois from March to November, sunsets will get as late as 8:29 p.m. under daylight saving time on June 20, which comes with a 5:15 a.m. sunrise, according to timeanddate.com.
If Chicago and the rest of Illinois continued to observe standard time after the early March switch, both the sunrise and sunset times at the peak of summer would be an hour earlier, with a 4:15 a.m. sunrise and 7:29 p.m. sunset.
Maintaining standard time would mean earlier sunsets overall, which would include a 6:03 p.m. sunset on March 20, as opposed to a 7:03 p.m. sunset that Chicago will see on that date next year under the observance of daylight saving time.
What’s better: Daylight saving time or standard time?
The topic of daylight saving time vs. standard time has been hotly debated.
Sleep experts have advocated in some cases for a permanent standard time. Some experts also say switching to permanent daylight saving time would be worse.
“Permanent standard time would basically mean that we were on what is, I guess, biologically the correct time all year round. And I’m going to say biologically correct because our bodies are more used to and have evolved to be on what would be considered standard time over the years,” Dr. James Rowley, a professor of medicine at Rush University and the immediate past president of the American Academy of Sleep Medicine told NBC Chicago in an interview. “Permanent daylight saving time, the particular problems come in at winter. It is great to have ‘the extra hour of sunlight’ in the evening, although I always remind people, we have the same amount of sun, you know, in the summer, whether it’s daylight or standard time, but just that seems to be an hour later. But in the winter time, sunrise is much later, and that’s very problematic biologically, because we need sunshine in the morning to set our circadian rhythms for the day.”
The American Academy of Sleep Medicine has pushed for a switch to permanent standard time for several years.
“By causing the human body clock to be misaligned with the natural environment, daylight saving time increases risks to our physical health, mental well-being, and public safety,” Dr. M. Adeel Rishi, who is chair of the AASM Public Safety Committee and a pulmonary, sleep medicine, and critical care specialist at Indiana University Health in Indianapolis, said in a statement. “Permanent standard time is the optimal choice for health and safety.”
Experts cited a “growing body of evidence” in recent years.
“Permanent standard time helps synchronize the body clock with the rising and setting of the sun,” Dr. James A. Rowley, president of the AASM, said in a release. “This natural synchrony is optimal for healthy sleep, and sleep is essential for health, mood, performance, and safety.”
It also mirrors similar takes from other organizations, including the National Sleep Foundation, which said “seasonal time-changes are disruptive to sleep health and should be eliminated.”
Permanent daylight saving time would lead to later sunrises across much of the U.S., with some states not seeing a sunrise until after 9 a.m. during portions of the year.
“Having sunshine in the morning actually helps us to fall asleep at nighttime. And the other problem is, of course, it’s darker later into the morning, which has its own set of problems with safety, driving, people walking. Parents are definitely worried about their kids walking to school in the dark,” Rowley said. “If we were on permanent daylight saving time, most of the United States would not have sunrise until after 8 a.m. and the northern states – you know, the particularly northern states like Minnesota, Montana, the Dakotas – would not have sunshine until after 9 o’clock in the morning. And so the American Academy of Sleep Medicine firmly believes that we should be on permanent standard time, not permanent daylight saving time.”
Still, Rowley noted that no legislation is currently being discussed to push for a switch to permanent daylight time, so a change in the near future is unlikely.
With clocks still changing, Rowley said there is growing evidence to suggest the body never fully adjusts to daylight saving time – even between spring and fall.
“Losing that hour of sleep [in the spring] for some people, just makes them more anxious, some more depressed, some more irritated. So it can be quite problematic. Problem is that, even long term, while we think we are adjusting to that change, there is actually evidence that we don’t completely adjust to the change, so we are still at increased risk for all those things throughout daylight saving time,” he said. “Plus, as I mentioned before, we need sunshine in the morning to help us fall asleep at night. But during the summer, if we have light too much late into the evening, that actually prevents us from falling asleep. So having that ‘extra light’ in the evening actually prevents sleep. So it just has its long term consequences as well.”
