Daylight Saving Time?

Have you ever wondered what people mean when they say “spring forward” and “fall back?” Or why it stays light out for longer in the summer than in the winter? Daylight Saving Time, or DST, is a system for uniformly advancing clocks. It extends daylight hours during typical waking times in the summer. Countries in the Northern Hemisphere set clocks ahead one hour in the spring. In the fall, they set the clocks back again. So, “spring forward” and “fall back.” The practice was first suggested in an essay by Benjamin Franklin. During World War I the U.S., the U.K., Australia, and Germany adopted DST to conserve energy by reducing the use of artificial light. During World War II some countries kept clocks continuously advanced by one hour. The U.K. kept clocks two hours ahead in the summer and one in the winter. Because the system changes with the seasons, there’s not really a definitive time to start and stop. The U.S. used to start DST on the last Sunday in April and end on the last Sunday in October. But in 1986 Congress passed a law that moved the beginning to the first Sunday in April, starting in 1987. The Energy Policy Act of 2005 changed the system again. Now DST starts the second Sunday of March and ends the first Sunday in November. The change took place starting in 2007. Two U.S. states actually don’t follow DST. Hawaii does not, and neither does Arizona—except for the portion of the Navajo Nation that is in the state. They use DST to keep time consistent across the entire Navajo Nation, which spans multiple states. But the Arizona part of the Navajo Nation surrounds the Hopi Nation, which doesn’t use DST, along with the rest of Arizona. So you can get into a weird time wormhole driving through the state! Fewer than 40 percent of the world’s countries follow DST. The system is used in the U.S. and much of Canada, the U.K., much of Europe, southern Australia, and New Zealand. Other notable clock-switching countries include Chile, Paraguay and a few in the Middle East. Some people aren’t the biggest fans of changing the time. It’s hard to give up an extra hour of sleep in the spring. And in the fall, it often gets dark before the end of the workday. In 2022 a bill called the Sunshine Protection Act unanimously passed in the U.S. Senate. This would have made DST the permanent time. However, the bill stalled in the House—so, as of 2023, you still need to double check your clocks when you go to bed.