Over one billion people in about 70 countries are affected by Daylight Saving Time each year. In the United States, the only states that do not observe Daylight Saving Time are Hawaii and most of Arizona. The U.S. possessions of Guam, Puerto Rico, the U.S. Virgin Islands, and American Samoa are also on standard time year-round. Since 2007, the U.S. has observed Daylight Saving Time from the second Sunday in March until the first Sunday in November.
Origins of Daylight Saving Time
As noted in the movie, “National Treasure,” Benjamin Franklin first had the idea of waking earlier to take advantage of the sunlight. Franklin was serving as a minister to France in 1784 when he sent a letter to the Journal of Paris. In the letter, he humorously described how he was awakened by a loud noise one April morning, several hours earlier than his normal noon rising, and was astonished to see his room full of light yet with no candles or lamps burning. He went on to suggest that all Parisians rise seven hours earlier in the morning, and thus go to bed earlier in the evening, to decrease the hours of darkness that people were awake and would need to use candles. Franklin estimated this would save Paris residents 64,050,000 pounds of tallow and wax for half a year.
Although Franklin’s letter to the Journal was largely in jest, the idea of rising earlier during the summer months was introduced again in Britain by William Willett, a builder, after a morning horseback ride in 1905. Willet tried for years to have clocks moved ahead one hour in the summer and back one hour in the fall, but in 1908 the House of Commons rejected the idea. Willett died in 1915 without seeing his idea come to fruition.
Daylight Saving Time During the World Wars
Germany was the first country to adopt Daylight Saving Time during World War I, and Britain quickly followed suit when Parliament established British Summer Time in 1916. In 1918, the U.S. Congress put the entire country on Daylight Saving Time for the duration of the War. Adopting Daylight Saving Time allowed people to spend more time operating by daylight rather than artificial light, which saved precious fuel. Daylight Saving Time was unpopular in the U.S. after the War ended, and Congress repealed the national law. Some local areas observed Daylight Saving Time on their own schedules.
When World War II began, Congress quickly re-instituted year-round Daylight Saving Time, which lasted until September 30, 1945. Other countries also acted quickly to institute the energy-saving measure, and England went so far as to set clocks back two hours during the summer months, called Double Summer Time, and kept clocks one hour back during the winter.
The Uniform Time Act of 1966
After the end of WWII, individual localities again observed Daylight Saving Time on their own schedules. This resulted in mass confusion and occasionally chaos, especially with the transportation and broadcasting industries. The Uniform Time Act of 1966 established standard dates for Daylight Saving Time, beginning the last Sunday in April and ending the last Sunday in October. Observation of Daylight Saving Time was not mandated; however if a state or locality wanted to observe the time change, they had to do so on the dates set by the Act. An amendment in 1986 moved the beginning date forward to the first Sunday in April. The European Union adopted standardized Daylight Saving Time dates in 1996; the dates, which had been used by the United Kingdom for many years, are the last Sunday in March to the last Sunday in October.
Energy Conservation and Daylight Saving Time
The Arab Oil Embargo of 1973 created an energy shortage in the United States, and in an effort to save energy Congress extended the dates of Daylight Saving Time during the crisis. In 1974, Daylight Saving Time began on January 6, and in 1975 it began on February 23. The ending date of the last Sunday in October was not changed.
In 2005, Congress enacted the Energy Policy Act, which changed Daylight Saving Time dates again. As of March 2007, Daylight Saving Time begins on the second Sunday in March and ends on the first Sunday of November. States and territories are still able to choose not to observe Daylight Saving Time. The state of Indiana, which was once split in its observation of the time change, adopted a whole-state observation in 2006.
Research on the advantages of observing Daylight Saving Time has supported the idea that the time change saves energy. Studies on the energy crisis of the 1970s showed that Daylight Saving Time decreased energy usage in the United States by about one percent per day. A 2009 study indicated the time change reduced energy usage by about one-half of one percent per day, a seemingly small amount that in aggregate would provide power to 122,000 U.S. homes for one year.