Those of you still recovering from last weekend's Halloween festivities will be pleased to know that Daylight Saving Time (DST) ends on November 7, 2021. On Sunday, most North Americans will move their clocks back by an hour, ensuring them an extra hour of sleep. The simple act will also afford them an extra hour of daylight during the shorter winter days.

Benjamin Franklin was the first to suggest manipulating the clocks in 1784. However, the American inventor, who proposed the idea in a letter to the Journal of Paris, was not serious about making the change. In 1895, George Hudson suggested moving clocks back by two hours. The New Zealand entomologist was hoping for extra daylight hours to study insects. His request and that of Britain's William Willett — who proposed it as a way to save electricity costs in 1907 — fell on deaf ears.

DST finally became a reality in April 1916, when Germany advanced clocks by an hour to conserve fuel to produce weapons for World War I. The US and Britain also adopted the change. All reverted to Standard Time once the conflict ended, only to reinstate DST during World War II. When the war ended in 1945, US officials repealed DST in the country. However, states and districts were allowed to continue the practice and even decide on the start and stop dates.

The seemingly good idea soon turned into what Time Magazine referred to as a "chaos of clocks." By 1965, Iowa alone had 23 different sets of DST start and end dates. The US Congress ended the confusion with the 1966 Uniform Time Act that established a predetermined "Spring Forward" and "Fall Back" date for the entire nation. Since the law was not mandatory, Hawaii, most of Arizona, and the US territories — Puerto Rico, Guam, the Northern Marina Islands, and the US Virgin Islands — opted out.

The initial DST start and end dates were scheduled for the final Sundays in April and October, respectively. They have been changed multiple times since. In 1986, President Ronald Reagan moved the start date to the first Sunday in April. The Energy Policy Act of 2005 brought the start date forward to the second Sunday in March and extended the end date to the first Sunday in November.

The benign gesture of changing clocks back and forth has some unexpected consequences. For instance, the end of DST can alter the birth order of twins born close to 2:00 am, when the official time change occurs. If the first child is born at 1:45 am, and the second, twenty minutes later, at 2:05 am, he/she would become the firstborn. That's because the time change reflects the official birth time as 1:05 am. Conversely, since we magically "lose" an hour when DST starts in spring, no babies are born between 2:00 and 3:00 am.

DST, which is observed by about 1.5 billion people in 70 countries worldwide, has always been somewhat controversial. Many people believe the time change has an adverse effect on health. However, lawmakers have been reluctant to stop the custom due to the purported negative impact on businesses. So, unless you live in Hawaii, Arizona, or the US territories, you have no choice but to turn back the time and enjoy the bonus hour on November 7.

Happy Fall Back!