Call & Times

Did you remember to move your clocks ahead?

- By MATTHEW CAPPUCCI

Would you trade a one-time hour of sleep loss in exchange for an entire season of later sunsets? You won’t have much choice in the matter Saturday night. After four months, we’ve returned to daylight saving time.

Hopefully you remembered to turn you clocks ahead one hour at 2 a.m. Sunday, effectivel­y making it 3 a.m.

We lose an hour of sleep, but only for one night. It’s just to shift us toward later sunsets until November.

Of course, this will come with later sunrises, but most of us would prefer that sunlight at the end of the day, after work, when we can enjoy it. Waking up in the dark seems like a fair trade.

The exception will be Ar- izona, which, save for the Navajo Reservatio­n, remains on daylight standard time all year long. That means they’ll keep the earlier sunsets. Their logic was that the characteri­stically hot climate meant cooler, darker evenings would be a welcome respite from the heat.

After a winter of short days and cruel sunsets sometimes falling before 5 p.m., many in the Northeast and Mid-Atlantic yearn for the commenceme­nt of daylight saving time. It heralds the first noticeable step to springtime, with the weather eventually following suit and the days becoming longer. In fact, the days grow longer by a greater margin during the next two weeks than any point all year. Daylight is increasing by roughly 2 ½ minutes each day.

The annual shortening of the days in the months leading up to winter – and gradual regaining of sunlight in the spring – comes thanks to the Earth’s 23.5-degree tilt on its axis.

Regions near the equator experience the most direct sunlight averaged over the year, which is why the tropics are the warmest. On the equator itself, every 24-hour period is divided into equal parts day and night. That’s why every day is exactly twelve hours long. The same is true about night. Sunrise and sunset times might wobble a few minutes up or down over the course of the year, but the length of daylight will never change.

But near the poles, it’s a different story. Earth’s tilt means that regions in the Arctic or Antarctic can be facing away from the sun in the shadow of other parts of the globe for weeks or even months at a time. That’s the premise behind “polar night,” during which the sun plunges below the horizon around the start of winter and doesn’t emerge until spring approaches. Utqiagvik, Alaska – the northernmo­st town in the United States – is shrouded in inescapabl­e darkness from Nov. 19 to Jan. 22 each year.

In the summertime, that effect is reversed. The sun doesn’t set in Utqiagvik between May 11 and Aug. 1. Talk about a long day.

Day length varies the most at the poles and least at the equator. In between, the annual variabilit­y is a bit more moderate. In Chicago, the difference between the shortest and longest day of the year is 6 hours, 6 minutes. Closer to the equator in Miami, that difference is 3 hours, 14 minutes. And during the summer, days are actually longer in Chicago than in Miami.

How can that be? After all, Miami’s average annual temperatur­e is 27 degrees higher than Chicago’s. It has to do with sun angle. Every place on Earth gets the same number of hours of daylight if you added them up over a year. But not all sunlight is equal. Closer to the equator, it’s more direct. Near the poles, it comes in at a sharper angle, meaning the same beam of light has to warm a greater stretch of land – and the effective warming is less. That’s also why we have seasons.

Daylight Standard Time – which we abide by in winter – was invented to compensate for the dwindling of daylight in the winter. It was believed that the daylight would be more useful in the morning than the evening, so the clocks were shifted in an attempt to move peoples’ schedules up. Nowadays, it’s a leftover antiquity dating back to the days of being a primarily agricultur­al and industrial nation.

Most 21st century Americans dislike the current system of switching clocks, preferring instead the idea of making summertime saving time the norm year-round. It’s gaining some traction in government­s.

A new bill introduced in California would do just that and has been met with overwhelmi­ng support. If passed, the Golden State could lead the nation’s fight to abolish winter’s standard time. The San Francisco Chronicle reports at least 28 other states have some form of legislatio­n seeking to do the same.

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