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Daylight saving time, its history and why we use it
Daylight Saving Time Saves Energy
History of Daylight Saving Time
Embargo Changes Daylight Saving Time
Congress and President Reagan Change Daylight Saving Time
More Information

Spring forward...Fall back....

It's ingrained in our consciousness almost as much as the A-B-Cs or our spelling reminder of "i before e...." And it's a regular event, though perhaps a bit less regular than the swallows coming back to Capistrano.

Yet in those four words is a whole collection of trivia, facts and common sense about Daylight Saving Time.

In 2005 and 2006, Daylight Saving Time begins for most of the United States at 2 a.m. on the first Sunday of April. Time reverts to standard time at 2 a.m. on the last Sunday of October.

Beginning in 2007, Daylight Saving Time is extended one month and begins for most of the United States at:

2 a.m. on the Second Sunday in March
to
2 a.m. on the First Sunday of November.

The new start and stop dates were set in the Energy Policy Act of 2005.

Daylight Saving Time -- for the U.S. and its territories -- is NOT observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, and by most of Arizona (with the exception of the Navajo Indian Reservation in Arizona).

Other parts of the world observe Daylight Saving Time as well. While European nations have been taking advantage of the time change for decades, in 1996 the European Union (EU) standardized a EU-wide "summertime period." The EU version of Daylight Saving Time runs from the last Sunday in March through the last Sunday in October. In the southern hemisphere where summer comes in December, Daylight Saving Time is observed from October to March. Equatorial and tropical countries (lower latitudes) don't observe Daylight Saving Time since the daylight hours are similar during every season, so there's no advantage to moving clocks forward during the summer.

One of the biggest reasons we change our clocks to Daylight Saving Time (DST) is that it saves energy. Energy use and the demand for electricity for lighting our homes is directly connected to when we go to bed and when we get up. Bedtime for most of us is late evening through the year. When we go to bed, we turn off the lights and TV.

In the average home, 25 percent of all the electricity we use is for lighting and small appliances, such as TVs, VCRs and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, we can cut the amount of electricity we consume each day.

Studies done in the 1970s by the U.S. Department of Transportation show that we trim the entire country's electricity usage by about one percent EACH DAY with Daylight Saving Time.

Daylight Saving Time "makes" the sun "set" one hour later and therefore reduces the period between sunset and bedtime by one hour. This means that less electricity would be used for lighting and appliances late in the day.

We also use less electricity because we are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When we are not at home, we don't turn on the appliances and lights. A poll done by the U.S. Department of Transportation indicated that Americans liked Daylight Saving Time because "there is more light in the evenings / can do more in the evenings."

While the amounts of energy saved per household are small...added up they can be very large.

In the winter, the afternoon Daylight Saving Time advantage is offset by the morning's need for more lighting. In spring and fall, the advantage is less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year except for the four darkest months of the year (November, December, January and February) when the afternoon advantage is offset by the need for lighting because of late sunrise.

But why do we have Daylight Saving Time to begin with? Who created the laws and regulations that we follow?

Daylight Saving Time is a change in the standard time of each time zone. Time zones were first used by the railroads in 1883 to standardize their schedules. According to the The Canadian Encyclopedia Plus by McClelland & Stewart Inc., Canada's "[Sir Sandford] Fleming also played a key role in the development of a worldwide system of keeping time. Trains had made obsolete the old system where major cities and regions set clocks according to local astronomical conditions. Fleming advocated the adoption of a standard or mean time and hourly variations from that according to established time zones. He was instrumental in convening an International Prime Meridian Conference in Washington in 1884 at which the system of international standard time -- still in use today -- was adopted."

In 1918, the U.S. Congress made the U.S. rail zones official under federal law and gave the responsibility to make any changes to the Interstate Commerce Commission, the only federal transportation regulatory agency at the time. When Congress created the Department of Transportation in 1966, it transferred the responsibility for the time laws to the new department.

The American law by which we turn our clock forward in the spring and back in the fall is known as the Uniform Time Act of 1966. The law does not require that anyone observe Daylight Saving Time; all the law says is that if we are going to observe Daylight Saving Time, it must be done uniformly.

Daylight Saving Time has been around for most of this century. In 1918, in order to conserve resources for the war effort, the U.S. Congress placed the country on Daylight Saving Time for the remainder of WW I. It was observed for seven months in 1918 and 1919. The law, however, proved so unpopular that it was later repealed.

When America went to war again, Congress reinstated Daylight Saving Time on February 9, 1942. Time in the U.S. was advanced one hour to save energy. It remained advanced one hour forward year-round until September 30, 1945.

From 1945 to 1966, there was no U.S. law about Daylight Saving Time. So, states and localities were free to observe Daylight Saving Time or not.

This, however, caused confusion -- especially for the broadcasting industry, and for trains and buses. Because of the different local customs and laws, radio and TV stations and the transportation companies had to publish new schedules every time a state or town began or ended Daylight Saving Time.

By 1966, some 100 million Americans were observing Daylight Saving Time through their own local laws and customs. Congress decided to step in end the confusion and establish one pattern across the country. The Uniform Time Act of 1966 (15 U.S. Code Section 260a) created Daylight Saving Time to begin on the last Sunday of April and to end on the last Sunday of October. Any area that wanted to be exempt from Daylight Saving Time could do so by passing a local ordinance. The law was amended in 1986 to begin Daylight Saving Time on the first Sunday in April.

Following the 1973 Arab Oil Embargo, Congress put most of the nation on extended Daylight Saving Time for two years in hopes of saving additional energy. This experiment worked, but Congress did not continue the experiment in 1975 because of opposition -- mostly from the farming states.

In 1974, Daylight Saving Time lasted ten months and lasted for eight months in 1975, rather than the normal six months (then, May to October). The U.S. Department of Transportation -- which has jurisdiction over Daylight Saving Time in the U.S. -- studied the results of the experiment. It concluded:

• Daylight Saving Time saves energy. Based on consumption figures for 1974 and 1975, The Department of Transportation says observing Daylight Saving Time in March and April saved the equivalent in energy of 10,000 barrels of oil each day -- a total of 600,000 barrels in each of those two years. California Energy Commission studies confirm a saving of about one percent per day.


• Daylight Saving Time saves lives and prevents traffic injuries. The earlier Daylight Saving Time allowed more people to travel home from work and school in daylight, which is much safer than darkness. And except for the months of November through February, Daylight Saving Time does not increase the morning hazard for those going to school and work.


• Daylight Saving Time prevents crime. Because people get home from work and school and complete more errands and chores in daylight, Daylight Saving Time also seems to reduce people's exposure to various crimes, which are more common in darkness than in light.

The Department of Transportation estimated that 50 lives were saved and about 2,000 injuries were prevented in March and April of the study years. The department also estimated that $28 million was saved in traffic accident costs.

Newer studies, however, reportedly challenge the earlier claims of safety and crime prevention under DST. Further research probably is warranted.

President Ronald Reagan
Source: Official Portrait of President Reagan. 1985 Daylight Saving Time was changed slightly in 1986 when President Reagan signed Public Law 99-359. It changed Daylight Saving Time from the last Sunday in April to the first Sunday in April. No change was made to the ending date of the last Sunday in October.

This was done ostensibly to conserve energy during the month of April. Adding the entire month of April is estimated to save nationwide about 300,000 barrels of oil each year.

You can find out more information about Daylight Saving Time by writing TIME, c/o Office of General Counsel, U.S. Department of Transportation, Washington, D.C. 20590.

Another Web site about DST is a public service of the Institute for Dynamic Educational Advancement (IDEA) by WebExhibits as a compliment to www.time.gov.

The U.S. Naval Observatory's Web site gives the current time for all time zones, and it's free.

Daylight Saving Time differs in other areas of the world. Consult a good encyclopedia for additional information about DST in your own country. Or check out the following Web pages:

• worldtimezone
• worldtimeserver
• worldtime