Spring Forward !?!?!

America just went through its annual rite of passage, jumping forward to daylight saving time. It is always accompanied by another round of complaints, confusion, and protest. ^{Americans have so little to argue about, it’s a good thing they still have this} (^sarcastic font). In the end, it’s all a battle about sunlight, when you get it, and what you call it.

Let’s start with the basics. The amount of daylight one receives daily depends primarily on one’s latitude (a north-south measure). At the equator, it’s twelve hours daily, always. As you move north or south, days become increasingly longer (in summer) or shorter (in winter). The seasonal daylight change is actually due to the Earth’s inclination (tilt), but let’s not introduce astronomy, ok? So there’s little reason to fool with the clocks for lands near the equator, as the amount of sunlight at say 7:00 am is roughly the same, January through December. But as you move toward the poles and light becomes dearer in the dreary winter, your children will be waiting for the school bus in the dark, or you will be driving home from work at night. Likewise, plentiful Summer daylight could be wasted in bed, so the idea was born to simply change what we call the time to adjust that variable to when the sunlight is available.

Next subject is geography. Most countries lie in a single time zone. It is an odd coincidence that most countries are either roughly square or taller (north-south) than wider. While they may switch from standard to daylight saving times (and back) during the year, the whole country is affected uniformly. If your nation fits snugly into a time zone, the fact it gets dark at 5:00 pm in one city and 5:15 in another and 5:30 in a third is hardly worth arguing about.

The major exceptions to this rule are the United States, Canada, Russia, China, and Australia, which span multiple times zones. Russia spans the most (nine), followed by Canada (five and a half!), China (should be four, but is one), the continental USA (four) and Australia (three). Which of these things is not like the other? Only in the US is the population spread out both across and within the time zones. Russia and Australia have the bulk of their people in a single time zone and vast relatively unpopulated other time zones. China is likewise, but simply mandates everyone be on “Beijing time.” Screw you, Xinjiang if dawn is at 11:00 am! Canada has population spread, but is still relatively sparse. In three of the four continental US time zones, there are several large cities on different (east-west) sides of a single time zone. Which means there are many people who will be advantaged or disadvantaged by being in the same time zone. When you try to make the bus stop happen in daylight in Boston, the commute home in Detroit is pitch dark, or vice versa). That is the simple reason it’s always been a contentious issue in the US, especially more so than in other countries.

Let’s take Mexico for example. The federal government did away with daylight saving (note there is no extra “s”) time last year. Mexico has four time zones, with the bulk of the population being in the Mexico City time zone. Quintana Roo (home of Cancún and the other resorts) mirrors US Eastern time, as that is where the bulk of its tourist business lives. Likewise, the Mexican border states mirror their northern cousins, switching or not to simplify travel and trade across the border. Mexico is in the tropics, so the real daylight change is between one and two hours at most, so no one is terribly disadvantaged and time doesn’t become a contentious issue.

Why do we even change times? It started as a wartime experiment when the US adopted it in 1918 during WWI. The idea was to economize on power and fuel by adjusting times so war industry workers had access to the most daylight in Summer. No one has ever definitively proved any real advantage to it, however. The initial opposition was attributed to farmers who complained about messing with Mother Nature, but this is probably apocryphal, since farmers work on natural schedules, and don’t care whether city folk call dawn 5:00 am or 6:00 am; it’s just when the animals need feeding.

Another silly argument to dispense with is based on the recurrent studies which show negative health effects from time changes. These are what is known as correlation–not causation–effects, meaning two things vary together but one does not cause another. If you ever heard the phrase “what does that have to do with the price of tea in China?” the meaning of that obscure saying is that you can find many variables that increase or decrease together, but no one should then assume one causes the other to change. How do we know there is no direct causation? If there was a causation between time changes and major negative health outcomes, the millions of business people and tourists who fly across the Atlantic and Pacific every day would be dying in droves. It doesn’t happen, so there is no causation, just correlation. What does happen is jet lag, which is lousy but not fatal.

What is very real is an increase in things like accidents when driving or walking at night, so forcing commuters or children to do so costs lives. But remember, making it work in New York means it doesn’t work in Indianapolis! There are workarounds. People in Xinjiang keep Beijing time officially, but do all their scheduling on “local time.” The central time zone in Australia is on a half hour offset, as is Newfoundland & Labrador in Canada. But that involves relatively small groups of people and places without that much travel between them.

So if daylight saving time is so great, why not keep it permanently? It’s only great in Summer, when it maximizes your time outdoors in the sunshine. The US tried this in 1974, when Congress repealed the “fall back” time change during the Summer of that year , and President Nixon signed the bill into law. Seventy-five percent of American supported the measure. When Winter came, the new Summer-focused time failed miserably (darkness for school busses, for example), leading to a massive change in public opinion and the repeal of the repeal by then-President Ford in October, 1974.

Time doesn’t have to change. Time changes probably don’t save power, or fuel, but they also don’t make you sick. What they do, do, is maximize your access to plentiful sunlight in both Summer and Winter. If that’s important to you, embrace DST. Or move to Singapore. But please stop complaining!