The easiest way to understand why we changed the time this morning is this map

The story is well known: during the Second World War, practically all the countries of Western Europe they changed time zone. In some cases, it was because of the invasion of Nazi Germany; in others, it was a (more or less) voluntary decision of the different countries. Be that as it may, they changed to Berlin time. However, that is not what is striking. What is really striking is that, after the war, none of these countries returned to their previous zone. The explanation, although it may not seem so, is much more solid than it seems.

When we agreed to change the time…. when in 1912 is celebrated the International Radiotelegraph Heure Conference and the system of 24 time zones was approved, it was based on an astronomical phenomenon that was very useful: the fact that noon is stable throughout the year. That is, it happens almost every exact twenty-four hours. Thanks to this, setting the time of each place in the world (adopt the time zone) turned out to be something really simple and powerful. Revolutionary in many respects, indeed. Then the problems started.

The problems began because the events happened. The First World War meant that the international time convention was not even ratified by its members until 1919. After that, the different countries began to progressively unify their timetables. In Spain, we had been on the Greenwich meridian since January 1, 1901, like most European countries, under the Meridian conference of 1884. The new convention, instead, required many countries to change their time.

At that time the arguments were clear: ‘normalizing’ and ‘standardizing’ the time was necessary to the extent that rail transport, airships and the incipient aviation began to play a more important role in people’s lives. Having a different schedule for each city (as was the case until then) made everything much more complex than necessary. Coordination costs were beginning to be unaffordable.

And then people did what they wanted…. The problem is that this hourly ‘rationalism’ was optimistic. What Sandford Fleming had pointed outthe ‘father of time zones‘ in 1884, “the adoption of the correct principles of reckoning of time will not seriously alter or change the habits to which you are accustomed. You will lose nothing of value. The Sun will rise, it will set, and it will regulate all social usages. […] People will get up and go to bed, start and stop work, eat breakfast or dinner at the same current time intervals, and our social habits and customs will not change.”

And that is exactly what happened. People continued with their lives adapting to the Sun. The surprising thing, what the Meridian experts had not suspected, is that, although noon is stable and that is very useful for us to establish the spindle; society is not governed by solar noon, it is governed by dawn. And that, as we will see, is not governed by conventional time zones. For this reason, to the surprise of many, the change of time zone to adapt to Berlin came as “water in May” for something else: to adapt the civil timetable to the one that citizens really had.

When does sunrise in Europe? The key to understanding why, despite the bad press, we’re still in Berlin’s time zone is on the map above. The simulation made by an old acquaintance from Xataka, the professor at the University of Seville and the country’s leading expert on the subject Martin OlalaThis allows us to answer this question very clearly. In winter, when it is daytime in Orense, Madrid, or Barcelona, ​​it is not daytime in London. In fact, it is daytime in Las Palmas de Gran Canaria and that, regardless of the time zone that would theoretically be up to each one.

In general, we take winter as a reference for the simple reason that it is when there are fewer daylight hours. It gives us the “minimum interval” of reference. If we adjusted the civil time with the summer, the days would be completely decoupled from noon and we would spend a good part of the winter day in the middle of the night. If we evaluate it objectively, despite the problems caused by having more daylight hours, this is the arrangement that has the fewest drawbacks.

In addition, due to the latitude of the Peninsula and the Balearic Islands (around the 40th parallel), many of these problems can be solved simply by changing the time twice a year. That is, moving civil time to get closer to the actual sunrise. This cannot be done in countries with a lower and/or higher latitude. This is the reason, in the end, why countries like Portugal were so combative in their decision to keep the time change and the reason why it remains in Spain despite its bad image.

Why is there such a problem with the spindle, then? Mainly for spring and summer. If we look at the following map, we will see that the sun strikes much less obliquely and that causes the sunset to fit much better with the time zones. The result is that, the imbalance that we drag, causes that in Galicia it gets dark much later than what would be “normal” or desirable.

This is a real problem and could obviously be fixed by introducing an extra time zone for Galicia (in the portuguese way) or for the Balearic Islands (as has also been claimed), but traditionally it has been considered that it would generate many coordination problems and very few comparative advantages. Is it so? The truth is that it is difficult to say. The only thing we can point out, because we have more than a hundred years of evidence for it, is that we can make the changes we want… people will continue to behave as before.

Image | JM Martin Olalla