Daylight Saving Time
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, Northern Mariana Islands, Puerto Rico, the Virgin Islands, and most of Arizona.