Daylight Saving Time (DST) is all set to kick in on Sunday, March 8, 2015, 2AM. This is when people in most parts of the U.S. will push their clocks ahead by one hour to Sunday, March 8, 2015, 3AM local daylight time.

Sunrise and sunset will occur approximately one hour later than the day before and the extra hour of daylight in the evenings marks the approach of spring and summer. There will now be more light in the evening, thanks to the normal course of the Earth's movements with respect to the sun.

Most smartphones, computers, tablets and other digital devices will re-adjust the time automatically, while analog alarm clocks will have to be moved ahead manually on Saturday, March 7, or the next morning.

Clocks are changed to DST mainly to save electricity, as the usage of electricity in residences is driven by the time people go to bed at night and get up in the morning. Through the year, most people turn off all the lights and television and go to bed when it's late evening.

But not all states in the U.S. will adjust for DST, with a few states and territories, including most of Arizona, Hawaii, American Samoa, Guam, Puerto Rico and the Virgin Islands, continuing to follow Standard Time.

DST means a lost hour of sleep. But come November 2015, clocks in the U.S. will be turned back by an hour and return to Standard Time on the first Sunday of the month. Until then, a cup of strong coffee will keep those losing an hour's sleep going.