8 Surprising Facts About Daylight Saving Time

The fascinating history behind changing the clock

AARP (Getty Images)

Sarah Elizabeth Adler,

Updated March 06, 2025

AARP

En español

Published March 08, 2022

/ Updated March 06, 2025

For most of us, it’s a predictable (if annoying) routine to “spring forward” and reset our watches and clocks for daylight saving time each year. But how much do you really know about the time change, which starts on Sunday, March 9, 2025? Read on to find out:

1. It’s daylight saving time, not daylight savings time

While it’s common to hear people say “daylight savings time” or just “daylight savings,” the correct term is “daylight saving time.” There’s a grammatical reason for keeping “saving” singular, but you can also think of it this way: What are you doing during this time? Saving daylight. Thus, daylight saving time.

2. Ben Franklin didn’t invent it

“The biggest misconception is that it was Ben Franklin’s idea,” says Peter Geiger, editor of the Farmers’ Almanac. While Franklin is often credited with inventing the concept of daylight saving time as we know it, he merely suggested that Parisians wake up earlier to save money on lamp oil and candles in a satirical essay published in the Journal de Paris in 1784.

3. It wasn’t implemented for farmers, either

Another misconception? That the practice originated to benefit farmers. In fact, the agricultural industry lobbied against daylight saving time after it was introduced in the United States. Many farmers continue to oppose the practice, which can disrupt farmwork. For example, dairy cows expect to be milked at the same hour each day — regardless of what the clock says.

4. Germany was the first country to implement daylight saving time

Germany implemented daylight saving time in 1916 to save fuel during World War I. The United States adopted the practice in 1918, but daylight saving time wasn’t standardized across the country until the passage of the 1966 Uniform Time Act, which gave the federal government oversight over the time change.

5. It’s not a worldwide (or even nationwide) phenomenon

About 70 countries observe daylight saving time nationwide or in certain regions. Most African and Asian countries, including India, China and Japan, skip the clock change altogether.

Not all U.S. states practice daylight saving time, either. Hawaii and Arizona are on permanent standard time, as are Guam, American Samoa, Puerto Rico and the Virgin Islands.

6. The time frame used to be different

In the United States, daylight saving time starts on the second Sunday of March and ends the first Sunday in November. But that wasn’t always the case, Geiger says. Before the Energy Policy Act of 2005, which went into effect in 2007, daylight saving time was observed from early April until late October.

7. It has an impact on your health

Losing an hour of sleep each March can take a serious toll on your well-being. The shift to daylight saving time has been linked to an uptick in heart attacks, strokes, traffic fatalities and workplace injuries — and some sleep experts have called for an end to springing forward altogether.

8. Many states want to stop changing the clock

Numerous states have passed legislation or resolutions to make daylight saving time permanent. However, federal law stands in the way of this change. Under the Uniform Time Act of 1966, states can either follow the current system of switching between standard and daylight saving time or opt out of daylight saving time entirely—but they cannot make it permanent without congressional approval.

Since 2018, lawmakers have introduced multiple versions of the Sunshine Protection Act to address this. In 2022, the Senate unanimously passed the bill, but the House never brought it to a vote. In December 2024, President Donald Trump expressed support for ending the practice of changing clocks in a social media post.

Sarah Elizabeth Adler joined aarp.org as a writer in 2018. Her pieces on science, art and culture have appeared in The Atlantic, where she was previously an editorial fellow, California magazine and elsewhere.