Daylight Saving Time, Beth Cook, Information Research Specialist. March 9, 2016: “Daylight Saving Time (DST) is a period of the year between spring and fall when clocks in the United States are set one hour ahead of standard time. DST is currently observed in the United States from 2:00 a.m. on the second Sunday in March until 2:00 a.m. on the first Sunday in November. The following states and territories do not observe DST: Arizona (except the Navajo Nation , which does observe DST) , Hawaii, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the Virgin Islands.”