Under the Uniform Time Act, as amended, States may exempt themselves from observing Daylight Saving Time by State law. If a State chooses to observe Daylight Saving Time, it must begin and end on federally mandated dates.
Daylight Saving Time is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, and most of Arizona.
Purpose of Daylight Saving Time
Daylight Saving Time is observed for several reasons:
- It saves energy. During Daylight Saving Time, the sun sets one hour later in the evenings, so the need to use electricity for household lighting and appliances is reduced. People tend to spend more time outside in the evenings during Daylight Saving Time, which reduces the need to use electricity in the home. Also, because the sunrise is very early in the morning during the summer months, most people will awake after the sun has already risen, which means they turn on fewer lights in their homes.
- It saves lives and prevents traffic injuries. During Daylight Saving Time, more people travel to and from school and work and complete errands during the daylight.
- It reduces crime. During Daylight Saving Time, more people are out conducting their affairs during the daylight rather than at night, when more crime occurs.