( CNN ) -- It 's that time of year again . This weekend , you 'll sacrifice an hour of sleep in exchange for a few months of extra daylight . Daylight Saving Time officially started at 2 a.m. on Sunday . If you have n't set your clocks forward yet , do it before you return to work on Monday . Daylight Saving Time ends the first Sunday in November . Benjamin Franklin first thought up the idea of daylight saving in 1784 . It was n't instituted until World War I , when it went into effect to save energy used for lights . The Standard Time Act established time zones and daylight saving in 1918 , but it was short-lived . Daylight saving was repealed the following year . Daylight Saving Time may bring health problems . The Uniform Time Act of 1966 established Daylight Saving Time throughout the United States and gave states the option to exempt themselves . Hawaii and most of Arizona do not follow Daylight Saving Time . Guam , Puerto Rico , the Virgin Islands and American Samoa also skip out on the clock-changing fun . In 1974 and 1975 , Congress extended daylight saving to save energy during the energy crisis . In 2007 , Daylight Saving got a few weeks longer , running from the second Sunday in March to the first Sunday in November . About 70 countries around the world observe daylight saving , but many countries near the equator do not . It 's not universally popular , though . Farmers note that their livestock do n't live by a clock , and complain that they have to adjust their working hours to deal with the animals . Also , any parent will tell you -- babies do n't quite get it either . Which do you prefer -- more daylight or more sleep ? Weigh in below .
Set your clocks forward Sunday . Daylight Saving Time started the first Sunday in November at an hour and runs through the first Sunday in November . About 70 countries observe daylight saving .