“Most of the United States begins Daylight Saving Time at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.”
“By act of Congress, civil clocks in most areas of the United States are adjusted ahead one hour in the summer months (known as daylight time) and returned back one hour in the winter months (known as standard time).
“On the first Sunday in November, clocks are set back one hour at 2:00 a.m. local daylight time (which becomes 1:00 a.m. local standard time). These dates were established by Congress … ” – Read more about Daylight Standard Time and its history at the United States Navy’s Astronomical Applications Department Website.