Fall Back (tonight) - Spring Forward

On Sunday, November 6, 2011 at 2 a.m., Daylight Saving Time ends in the United States.

OR

Tonight we change our clocks

“Clocks slay time... time is dead as long as it is being clicked off by little wheels; only when the clock stops does time come to life”
William Faulkner

Many fire departments encourage people to change the batteries in their smoke detectors when they change their clocks because Daylight Saving Time provides a convenient reminder. "A working smoke detector more than doubles a person's chances of surviving a home fire," says William McNabb of the Troy Fire Department in Michigan.


More than 90 percent of homes in the United States have smoke detectors, but one-third are estimated to have dead or missing batteries.

For millennia, people have measured time based on the position of the sun; it was noon when the sun was highest in the sky. Sundials were used well into the Middle Ages, at which time mechanical clocks began to appear. Cities would set their town clock by measuring the position of the sun, but every city would be on a slightly different time.

The time indicated by the apparent sun on a sundial is called Apparent Solar Time, or true local time.

The time shown by the fictitious sun is called Mean Solar Time, or local mean time when measured in terms of any longitudinal meridian.

Although not punctual in the modern sense, ancient civilizations adjusted daily schedules to the sun more flexibly than modern DST does, often dividing daylight into twelve hours regardless of day length, so that each daylight hour was longer during summer. For example, Roman water clocks had different scales for different months of the year: at Rome's latitude the third hour from sunrise, hora tertia, started by modern standards at 09:02 solar time and lasted 44 minutes at the winter solstice, but at the summer solstice it started at 06:58 and lasted 75 minutes. After ancient times, equal-length civil hours eventually supplanted unequal, so civil time no longer varies by season. Unequal hours are still used in a few traditional settings, such as some Mount Athos monasteries and all Jewish ceremonies.

The main purpose of Daylight Saving Time (called "Summer Time" in many places in the world) is to make better use of daylight. We change our clocks during the summer months to move an hour of daylight from the morning to the evening. Countries have different change dates.

The official spelling is Daylight Saving Time, not Daylight SavingS Time.

Who Does – Who Doesn’t

In the U.S., clocks change at 2:00 a.m. local time. In spring, clocks spring forward from 1:59 a.m. to 3:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m. In the EU, clocks change at 1:00 a.m. Universal Time. In spring, clocks spring forward from 12:59 a.m. to 2:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m.

Most of the United States begins Daylight Saving Time at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.

In the U.S., 2:00 a.m. was originally chosen as the changeover time because it was practical and minimized disruption. Most people were at home and this was the time when the fewest trains were running. It is late enough to minimally affect bars and restaurants, and it prevents the day from switching to yesterday, which would be confusing. It is early enough that the entire continental U.S. switches by daybreak, and the changeover occurs before most early shift workers and early churchgoers are affected.

However, many states restrict bars from serving alcohol between 2:00 a.m. and 6:00 a.m. At 2:00 a.m. in the fall, however, the time switches back one hour. So, can bars serve alcohol for that additional hour? Some states claim that bars actually stop serving liquor at 1:59 a.m., so they have already stopped serving when the time reverts to Standard Time. Other states get solve the problem by saying that liquor can be served until "two hours after midnight." In practice, however, many establishments stay open an extra hour in the fall.

For the U.S. and its territories, Daylight Saving Time is NOT observed in Arizona and the Hopi Reservation, (which is entirely surrounded by the Navajo Nation), Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, the Commonwealth of Northern Mariana Islands.

The Navajo Nation participates in the Daylight Saving Time policy, even in Arizona, due to its large size and location in three states.

Most of the world (except for countries around the Equator) have implemented DST at one point or another.

Today, approximately 70 countries utilize Daylight Saving Time in at least a portion of the country. Japan, India, and China are the only major industrialized countries that do not observe some form of daylight saving.

Equatorial and tropical countries (lower latitudes) generally do not observe Daylight Saving Time. Since the daylight hours are similar during every season, there is no advantage to moving clocks forward during the summer. China has had a single time zone since May 1, 1980, observing summer Daylight Saving Time from 1986 through 1991; they do not observe DST now.

Daylight saving time is now implemented in over seventy countries worldwide and affects over a billion people each year. Although many countries observe DST, the beginning and end dates are often different than the US. The European Union adopted the summer time period that was used in the United Kingdom for many years which begins on the last Sunday in March and ends on the last Sunday in October.


In the European Union, Summer Time begins and ends at 1:00 a.m. Universal Time (Greenwich Mean Time). It begins the last Sunday in March and ends the last Sunday in October. In the EU, all time zones change at the same moment.


Read on and see the timeline of Standard & Daylight Saving Time from the 1700's to today. Find out some interesting facts about Daylight Saving Time here in the U.S., around the world and just why doesn't Arizona switch to Daylight Saving Time.

When told the reason for Daylight Saving time the old Indian said,
"Only a white man would believe that you could cut a foot off the top of a blanket and sew it to the bottom of a blanket
and have a longer blanket."
Author Unknown

TNT