Daylight saving time in the U.S is the practice of setting the clock forward by one hour during the warmer part of the year,Daylight saving time starts on the second Sunday of March and ends on the first Sunday of November, with all time changes taking place at 2:00 A.M. local time.Arizona, Puerto Rico, Hawaii, U.S. Virgin Islands and American Samoa do not observe Daylight Saving Time.
The names in each time zone change along with Daylight Saving Time. Eastern Standard Time (EST) becomes Eastern Daylight Time (EDT), and so forth.