No, I do not like daylight saving time. It moves the clock further from, and even obscures, the rhythms of nature. So here’s my case. First, it’s confusing. There are folks who will tell you that the days get longer because we “spring forward.” Nope. Absolutely no effect. In mid-northern latitudes the length of day will go from about 9 hours, 30 minutes in December to 15 hours in June, whatever the clock hours read. DST only changes the clock hours in which we experience that daylight, displaces them, if you will, as anyone who has started to enjoy the earlier sunrises of the first week of March can tell you.
Most people, I admit, probably get that, so here is my deeper gripe. Daylight Time is arbitrary and has no basis in nature. You might think that’s true of any attempt to assign numbers to times of day, but no. Our 24-hour day was based on noon, which occurs every day when the sun reaches it highest point, even as the days and nights contract and expand. Well, actually it was based on Local Solar Noon, the moment the sun crosses the meridian as seen from your location, the moment when a correctly constructed and aligned sundial will read noon.
We have adjusted sundial time in two ways (not counting daylight time) over the centuries as technology has changed. Interestingly, the time from one noon to the next is not quite equal through the year. The earth’s rotation rate remains (practically) constant, but the its speed in its elliptical orbit increases when we are closest to the sun and slows when we are farther away. Thus the length of a sundial hour varies a little, according to the Equation of Time. This was no problem until we invented clocks whose error was less than that caused by the EoT. We averaged those variations out by using Mean Solar Time. Still, the concept of noon was the foundation.
|Local Mean Solar Time in Action
Mean solar time, however, was local. A clock set to mean solar noon in one city would not read the same as another. Gettysburg, for example, would be nine minutes behind Philadelphia and 10 minutes ahead of Pittsburgh. Every town having its own local time worked until travel and communication became fast enough to render it impractical. Thus, we got standard time, in which the time of one location became standard for a whole region. In the case of the Eastern Time Zone, we use the time for 75 degrees west longitude, or around Philadelphia. For the most part, we change clocks one hour after about every 15 degrees of longitude traveled, though there are a few half-hour time zones in the world. Still, with a couple of allowances, noon on your clock is near noon in the sky, especially if you do not live near the edge of a time zone. Noon connects us to the motion of the sun and to the day, in the literal sense of the word.
Daylight time discards that principle of time tied to the sun’s peak. Solar noon, from the second Sunday of March to the first Sunday of November, will be around 1:00 PM. I don’t like it one bit. I know we can’t all “make our noon” like ship captains of old. Standard time is fine; it makes necessary accommodations, but remains tied to the sun’s rise and fall. Daylight time is a government-created chimera that makes our clocks tell time, but not the time of day.