Do we actually benefit from daylight saving time?

Time is a fascinating concept, isn’t it? If you ever got the feeling that days are getting longer, well, your instincts are spot-on. People in countries such as Australia will soon be switching to daylight saving time.

Just as Australia sets its clocks forward by an hour for summer, the United States will be rolling the clock back for fall.

The switch will not apply to everyone. Only around 70% of Aussies will be setting their clocks forward, embracing those extra hours of sunshine. In America, states including Arizona and Hawaii do not observe daylight saving time.

But why do we have longer days in summer and shorter days in winter?

Tilted Earth and daylight saving time

Earth goes around the sun in an almost circular orbit. However, there’s a tiny catch. The axis of our beloved Earth is tilted by 23.44 degrees in relation to its orbit around the sun.

As Earth makes its merry way around the sun, this tilt remains as is. So, regardless of Earth’s position, the celestial stick stays at the same angle, unwavering in its tilted determination. This peculiar tilt is the reason behind our longer summer days and those cozy, shorter winter days.

The scenario gets interesting when you think about how this tilt affects each hemisphere differently. On one side of our orbit around the sun, the top of our metaphorical stick points towards the sun. This initiates summer in the Northern Hemisphere and winter in the Southern Hemisphere.

However, when Earth gets tired of this position and swaps sides, the bottom of the stick gets its time to shine (literally!) as it points towards the sun – ringing in winter for the North and summer for the South.

Winter and summer solstice

Remember the extremes we talked about when Earth is on either side of the sun? Those distinct points are known as the solstices. On June 21, Australians experience their shortest day of the year, while their longest day is on December 21.

In the time between these solstices lie the equinoxes, when day and night play fair and square, sharing the hours equally.

This equilibrium occurs when our celestial stick is perfectly “side-on” to the sun. In 2024, Australians can witness this balance on March 20 and September 22.

Length of a day on Earth

Daylight saving does a lot more than just rob us of an hour’s sleep (and add to our coffee intake). It rearranges our hours to give us more daylight in the evenings, which works wonders for night owls but isn’t the best news for morning larks.

This tilt of the Earth hasn’t always been at 23.44 degrees. Our intelligent planet cycles its tilt from a minimum of 22.1 degrees to a maximum of 24.5 degrees every 41,000 years or so.

Additionally, our day length hasn’t always been a precise 24 hours. The day duration shifts continually by minute amounts, tracked closely by a system of telescopes and satellites.

Interestingly, due to the moon’s gravitational pull, the length of our day is increasing by about 2.3 milliseconds every century.

Impact of daylight saving time

The cyclical changes in daylight and seasons have profound implications on human activities, affecting societal rhythms, agriculture, and even mood.

Historically, longer daylight hours helped farmers maximize their crops by increasing the time available for tending to fields. Similarly, industries that rely on natural light benefit from reduced energy costs during these extended periods.

Psychologically, the abundance of sunlight in the summer months is linked to elevated levels of vitamin D and enhanced mood, often resulting in increased productivity and well-being.

Conversely, the shorter days of winter can lead to seasonal affective disorder (SAD) in some individuals, a testament to the powerful influence of natural light on human health and behavior.

Future of daylight saving time

Debates continue regarding the efficacy and relevance of daylight saving time (DST) in today’s world.

Proponents argue that DST conserves energy by reducing the need for artificial lighting in the evenings, consequently lowering electricity consumption.

However, critics question its practical benefits, citing disruptions to human circadian rhythms and the limited energy savings in modern societies that operate less on solar time. Globally, the stance on DST remains divided, with some countries abandoning the practice altogether.

As technology advances and societies evolve, the future of daylight saving time may rest upon weighing its traditional purposes against the realities of contemporary life.

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