Permanent DST has already been tried in various countries around the world. It turned out to be extremely unpopular in practice and was always abolished due to public pressure [Roen19] .
Russia switched in 2011 from seasonal daylight saving time to year-round daylight saving time. After three years, Russia then switched to permanent standard time. A study that accompanied this test phase [BTPK17], showed: The social jetlag is much higher under permanent daylight saving time than under the seasonal one. The smallest social jetlag was found under permanent standard time. The number of people without social jetlag doubled, the proportion of people with more than 2 hours of social jetlag decreased by 25%.
The USA lived during the war from 1942 until 1945 with permanent daylight saving time. It was abolished after the end of the war. In 1974 the USA tried again permanent daylight saving with the goal to save energy. However, the desired savings were not observed. Before 1974, 79% advocated permanent daylight saving time. But by February, after the first winter, this support fell to 42%. The permanent daylight saving did not even survive 2 years: with 383 to 16 votes the congress ended the measure [Dayl20].
UK and Ireland
Great Britain and Ireland also lived year-round summer time during the war years 1940-1945, which was abolished again after the end of the war. In 1947 there was another attempt at a year-round summer time, which, however, did not even last two years. Great Britain and Ireland reintroduced the year-round summer time in 1968. Already after three years ago, in 1972, this was abolished because of complaints about long, dark winter mornings.
Portugal has already and repeatedly experimented with year-round DST and even double DST, all year round. Due to its negative impact on the population, it has also been repeatedly abolished.
In the recent history of the country, Portugal adopted the standard and seasonal DST of Germany in 1992 - Central European Time and Eastern European Time (UTC+01:00 and UTC+02:00, which corresponds to present day portuguese DST during winter and a double DST in summer) with economic interests and energy savings in mind. The opposite happened: an increase in energy costs was observed. There were no economic benefits, but instead an dire increase of serious health problems. In 1996, under a new government, the country reverted to the previous time zones (UTC±00:00 as standard time and UTC+01: 00 as DST) due to the complaints and overall malaise experienced by the population.
Forecast for Portugal
If the time change continues for Portugal, little will change. Portugal will waste a unique opportunity because, being in a geographically inadequate time zone, and putting the population during half the year in a time zone that only makes sense for those who live 2000 km to the east, has been responsible for keeping more than half of the population in constant tiredness. Portugal has not lived in a suitable time zone since ever, or better said, since the country joined the Washington Convention more than a century ago. No one currently living in Portugal has ever known what a time zone that allows a healthy life is, because there is no comparison. Ending this suffering is simple: listening to scientific facts. Considering the existing scientific facts, and the experiences of the past, experimenting with changed time zones and pointless DST is to induce unnecessary and cruel suffering. And a suffering country can never be a winning country.
Also Germany introduced permanent daylight saving time during the war in 1940, but abolished already in 1942 way before the war ended.
Forecast for Germany
If permanent summer time is introduced, there are two future perspectives.
One is that the permanent daylight saving time is abolished, as it was in Russia, the US and the UK. Considering the existing scientific facts, and the experiences of the past, trying permanent daylight saving time equals an unethical experiment on humans. On the population is tested what scientists have known already long time before.
And what happens after an abolition of daylight saving time is uncertain. Will Germany follow the US and the US and introduce the seasonal time change again or it will follow Russia and finally adopt permanently the correct time zone (standard time)?
In the worst case, people will close their eyes to the suffering that has arisen - out of pride that they were wrong; out of ignorance of scientific facts; out of selfishness. Then permanent daylight saving time will last until people have forgotten what a healthy life feels like because they no longer have the comparison. Over the years, social times will adapt to the new circumstances: schools and working hours will be delayed, meals will be pushed to later times. This has already happened in Spain, France and the Benelux countries, which have been living in the wrong time zone since World War II. Spaniards in particular are known for their late daily routines.But why this is so, people no longer know, nor will they know how it was before 1945, because the generation that still knows is dying out over time. Much like in Germany almost nobody knows anymore how beautiful a summer in standard time is - bright and rested.