How Many Minutes Do We Gain When Daylight Saving Time Starts?
Every year, you might wonder how many minutes of daylight people gain during certain times of the year. That’s a fair question, especially when you take the old adage “Fall back, Spring forward” into account. In the United States, a lot of these answers hinge on Daylight Saving Time (DST).
Twice a year, most Americans wake up after losing an hour of snooze time in early spring (or late winter) — or gaining an hour of sleep in late autumn. Daylight Saving Time impacts our sleep habits and, in part, regulates how much of the sun we’ll be seeing during business hours.
Without a doubt, DST plays a considerable role in our everyday lives. So, where did the idea come from, and why was it implemented? And, perhaps most importantly, why does it still exist? Let’s explore the logic behind the century-old practice and learn what sorts of time changes we’ll experience this year.
When Do Days Start Getting Longer?
As the sun moves higher in the sky between March and June, we gain two more minutes of daylight each day. After DST (beginning on the second Sunday in March at 2 a.m.), it’s easy to observe how much daylight is gained each day. It’s typically darker in the morning, and we have more sunlight later in the evening. Also, the higher someone’s latitude and further distance from the equator, the longer the sun remains above the horizon.
In August, the daylight loss rate starts to accelerate by two minutes each day until the winter solstice, between December 20 and 23. At the solstice, the North Pole sits farthest from the sun, becoming the shortest day of the year. During the summer solstice, on June 21, the Northern Hemisphere is closest to the sun, making it the longest day of the year.
From the vernal equinox in March through the summer solstice in June, the daylight exposure in the Northern Hemisphere increases. This is why people in Australia experience the winter season during what’s the summer season for those north of the equator.
Why Daylight Hours Change
To put it simply, the Earth controls this change–specifically, the Earth’s tilted axis. The axis that the Earth spins on is tilted at 23.5 degrees in relation to the axis it revolves around the sun every 365 days – or 366 days during a Leap Year. The tilted axis determines how many hours of daylight we have every day. Daylight changes depending on the latitude you live in.
For example, the parts of the Earth that are tilted towards the sun receive more than 12 hours of sunlight every day. On the other hand, the parts of the planet that face away from the sun receive less daylight. As the Earth revolves around the sun, the degree to which the part of the planet that is tilted towards or away from the sun changes throughout the year. You can track the exact times for sunrises and sunsets for your area, and even see a day length graph on several websites. This can help you identify how many hours of sunlight you will have each day.
The majority of the world uses DST to also track when we start gaining daylight in the spring and summer seasons, as well as when we start losing daylight hours in the fall and winter seasons. But, what’s the exact purpose and history of DST?
History and Purpose of Daylight Saving Time
Some people give Benjamin Franklin credit for the idea because of an essay he penned in 1784. Others claim either Canada or Germany established Daylight Saving Time in the early 1900s. Regardless, during World War I, the United States government needed a way to increase production while saving energy, and Daylight Saving Time, which takes advantage of the later hours of sunlight from April through October, seemed like a great solution. When the U.S. joined the war effort during World War II, the federal government required states to observe Daylight Saving Time.
Following World War II, the federal government afforded states the option of observing Daylight Saving Time. By 1966, Congress passed the Uniform Time Act, which standardized the length of Daylight Saving Time. Due to the Energy Policy Act’s passage in 2005, Daylight Saving Time was extended four weeks, lasting from the second Sunday in March through the first Sunday in November.
As stated, the idea behind Daylight Saving Time is to save energy. With this in mind, Congress signed the Energy Policy Act into law to save 10,000 barrels of oil each day. Lawmakers predicted a reduction in oil consumption by reducing the power utilized by businesses during the daylight hours. Unfortunately, it is nearly impossible to quantify the amount of energy savings, if there is any at all. Regardless of fossil fuel energy savings, Daylight Saving Time continues throughout most of the United States.
Daylight and Human Health
One universal complaint about Daylight Saving Time is that we “lose an hour” of sleep. Joseph S. Takahashi, Ph.D., Chair of the Department of Neuroscience at UT Southwestern, studied the effects of desynchronization on the human body. UT Southwestern Medical Center says, “this twice-a-year desynchronization of our body clocks has been linked to increased health risks such as depression, obesity, heart attack, cancer, and even car accidents.”
Every cell in the human body keeps track of time. Changes to daily routines lead to sleep deprivation, memory loss, difficulty learning, and cognitive function. In 1997, Dr. Takahashi’s lab discovered the CLOCK gene, “the first circadian gene in mammals.” Mutated CLOCK genes may cause delays in circadian functions “leading to dysfunctions in metabolic, behavioral, and cognitive abilities.”
By 2016, Dr. Takahashi’s laboratory discovered the first genes in mice that regulate sleep. The study turned up “two genes in mice that control how much rapid eye movement (REM) sleep and non-REM sleep is needed.” Healthy sleep patterns rely on lengthy non-REM sleep moments while the brain is not dreaming and processing memories. The findings suggest methods for improving sleep hygiene for the nearly 20% of the population who suffer from sleeping disorders. Therefore, Daylight Saving Time, and other external factors from the environment, play a considerable role in disrupting human health.
Where Is Daylight Saving Time Still Recognized?
Forty-eight states currently observe Daylight Saving Time. Arizona opted out of the practice in 1968 due to the excessive heat during the summer months. According to NASA, the Navajo Nation in Northeastern Arizona observes DST.
Hawai’i never observed Daylight Saving Time under the Uniform Time Act due to its tropical latitude. The state legislature briefly enacted Daylight Saving in 1933. However, the state repealed the law within three weeks. Additionally, the weather in Hawai’i rarely fluctuates, so Daylight Saving had virtually no effect on energy consumption.
The topic of Daylight Saving Time seems to resurface with each election cycle. In 2020, Florida Senators Marco Rubio and Rick Scott introduced the Sunshine Protection Act — a modern example of how Daylight Saving Time remains an essential topic of political and scientific conversation. Meanwhile, the European Union voted to eliminate biannual time changes in 2019. Several U.S. states are also considering similar laws due to the health risks.
This year, DST begins on March 13 and will end on November 6. Consider getting to bed earlier than usual and adjusting your clocks and alarms ahead of time.