What is Daylight Saving Time? Origin, how to calculate, and all you need to know about the annual spring forward

Starting this weekend, daylight saving time for 2024 took an hour off many people's sleep patterns when the clocks advanced. The time shift began on Sunday, March 10, early in the morning. Most Americans will benefit from an additional hour of sunlight until the next time the clocks change in the fall.

The start of DST is Sunday, March 10, at 2 a.m. Every year, DST runs from the second Sunday in March till the first Sunday in November. There will be no more daylight saving time after November 3, 2024, when clocks "fall back."

Daylight saving time is moving clocks forward to take advantage of the extended daylight hours during the summer and for darkness to fall later in the day. By expanding the time one may spend outside during the day, DST is meant to help people use daylight better.

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Daylight Saving Time is being practiced all over the USA

To maximize the amount of natural daylight available, DST is the practice of moving the clocks forward one hour from standard time in the summer and backward one hour in the fall.

People in places that observe daylight saving time will lose an hour on Sunday morning as the clocks "spring forward," going from 2 a.m. to 3 a.m. It means Sunday morning will feel more like 7 in the morning when a person wakes up at 8 a.m.

Hundreds of millions of Americans experience everyday disruptions from the time change, including clock changes, less sleep in the days that follow, and naturally, later sunsets.

While not all Northern Hemisphere nations observe DST throughout the summer, many do. Typically, DST begins in March or April and ends in September or November, when the nations switch back to standard time, commonly called winter time.

On the other hand, the participating nations in the Southern Hemisphere typically begin Daylight Saving Time in September or October and conclude it in March or April.

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When and how did the practice originate?

Posters by United Cigar Stores explained that DST was initially introduced in the US to conserve electricity during World War I. On July 1, 1908, Port Arthur, Ontario, Canada, became the first city in the world to implement DST. After that came Orillia, Ontario, which William Sword Frost founded while serving as mayor from 1911 to 1912.

The practice started in 1916, as previously reported by CBS News. That year, Germany practiced daylight saving time to save gasoline. The German Embassy notified the American Embassy in Washington, D.C., about the time change.

The source further reported that Germany thought the change in clocks would save millions of dollars by reducing the usage of artificial lights. Other European nations adopted the practice, and the United States began using it in 1918.

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How to calculate it?

The DST period often finishes in the fall or autumn, and the clocks are reset to regular time once more. The day of the shift is 25 hours long since people gain one hour in terms of clock time. From DST to standard time, local time jumps, effectively repeating an hour.

For the states that observe Daylight Saving Time, the easiest "time zone math" to recall is three-two-one. Three hours separate Eastern and Pacific time, two hours separate Eastern and Mountain time, and one hour separate Eastern and Central time.

For instance, in Florida, noon is at 11 a.m. ET, in Illinois, it is at 10 a.m., and in Colorado, it is at 9 a.m. On the other hand, in Florida, midnight signifies 11 p.m. ET, 10 p.m. in Colorado, 9 p.m. in California, and 11 p.m. in Illinois. It is 6:37 p.m. ET in Illinois, 5:37 p.m. in Colorado, and 4:37 p.m. in California if it is 7:37 p.m. in Florida.