Clocks change twice a year. They spring forward on the second Sunday in March and fall back on the first Sunday in November. The change occurs at 2:00 AM local time.
The correct term is Daylight Saving Time (without the "s"). However, many people commonly say "Daylight Savings Time."
Hawaii and most of Arizona do not observe Daylight Saving Time.
Daylight Saving Time was created to make better use of daylight during the longer summer months.