At the end of this month, on Sunday 30th March, we return to summer. On the last Sunday of March, Portugal, like other countries in the European Union, adjusts its clocks to start winter time. At 01:00, clocks advance to 02:00. The ritual, which is repeated on the last Sunday of October when the clocks are pushed back an hour, has raised the question: Why does time change?
“Daylight saving time” in English, translated as “daylight saving time”, explains the purpose of this practice. However, its practical consequences generate debates. For example, in autumn, even though mornings are bright, evenings come earlier, while in spring, the effect is reversed. The aim would be to make better use of natural light and theoretically save energy.
The history of time change goes back to proposals such as New Zealand entomologist George Hudson, who sought more daylight hours for his personal and professional activities. Later, William Willett (coincidentally the grandfather of Chris Martin, lead singer of Coldplay) championed the idea as a way to maximize outdoor leisure time and conserve energy. Although rejected at first, during World War I, many countries adopted the conversion to save fuel and energy.
However, the benefits of changing time vary depending on the latitude of each country. In mid-latitudes, such as Portugal, the practice is favorable, while in regions closer to the equator or the poles, the effects are less pronounced.
In 2018, the European Parliament conducted an online survey to gauge citizens' interest in maintaining or ending the time change. Although a majority voted in favor of ending the change, participation was low, and the final decision is still pending detailed studies of its impact.
In Portugal, the Permanent Time Commission is responsible for examining and proposing legal time-related measures. In 2021, a panel of experts signed the Barcelona Declaration on Climate Policies, citing benefits to health, the economy and the environment, arguing for an end to climate change.
The issue of climate change continues to raise debates and reflections on its true impact and relevance in modern times.
What if Daylight Saving Time is maintained?
Maintaining UTC+1 would be tantamount to maintaining summer time permanently, which happened between 1992 and 1996, during the Cavaco Silva government, when Portugal adopted the CET (Central European Time) time zone, as did the rest of Europe. At that time, in the height of winter, the sun rose around 9 am.
The justification given is that, although small, “energy savings and summertime sleep disturbances are negligible,” recalls the Porto Astronomical Observatory.