Stand on the Hoover Dam during the first week of March, and the two iconic clock towers that mark the border between Nevada and Arizona will be one hour apart, with Nevada on Pacific Standard Time and Arizona on Mountain Standard Time. But stand in the same spot a week later, when residents of 48 U.S. states have moved their watches forward one hour to observe Daylight Saving Time, and you’ll notice a strange thing: the Hoover Dam’s clock towers are no longer out of sync.
First introduced as a way to save on energy costs during the world wars, Daylight Saving Time (DST) was standardized by the Uniform Time Act of 1966. It normalized the “spring forward, leap back” concept, the idea being that moving time forward by an hour during the spring and summer months would lead to longer evenings with daylight and reduced energy usage.
But for residents of Arizona, which is known for its sunny days and high summer temperatures, this logic didn’t quite add up. A further hour of daylight in the summer equated to an additional hour under the sun’s oppressive heat and an additional hour of running the air conditioning. According to many of the state’s residents, the proposed measures made it harder for young children to go to bed and delayed the time when sunset activities, such as drive-in movies, could begin. So, in 1968, the Arizona legislature decided that the state would remain on Standard Time throughout the summer, making Arizona one of only two U.S. states not to observe Daylight Saving Time.
Take your time:
- The Navajo Nation, which is mainly in Arizona but also spans parts of Utah and New Mexico, does observe DST. However, the Hopi Reservation (surrounded by the Navajo Nation in northeastern Arizona) does not. So, if you drive east from Tuba City on Arizona State Route 264 while DST is in effect, you’ll go through six time zone changes in less than 100 miles.
- Hawaii is the only other U.S. state to have declined to observe DST, reasoning that its proximity to the equator ensures a good amount of sunlight, whatever time of year. The U.S. territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands also stick with Standard Time year-round.
- Putting the clocks forward and back twice a year is not without controversy, with studies linking the semiannual changes in time to increased workplace injuries, reductions in sleep patterns, and even an increased frequency of heart attacks.
