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Mar 07 2008

Summer Time

Posted by: roscivs, in politics

The phrase “Daylight Saving Time” never made much sense to me. You’re not saving any daylight—you’re just moving it around in the day. When I told this to N-san, he suggested the phrase, “Evening Daylight Extension Time,” which makes more sense.

DST has never really affected my life too much. I tend to wake up earlier in the summer naturally anyway, when the sun starts rising earlier, so when DST comes around I usually just change both my clock and my alarm, so I’m waking up a nominal hour later, but at the same unadjusted time. (And usually about an hour earlier than I do in the dead of winter.)

I was contemplating the usefulness of DST today, and I realized that most people don’t work like this. Either they don’t really have as flexible a schedule, or they just don’t have the fortitude to wake up earlier without a lying clock, but either way, I think the foundational principle of DST is that people wake up at the same time year round. Once I realized this fact, the other pieces started falling into place.

See, if the time zone is perfectly adjusted, then noon falls at the exact middle of the daylight hours. At a relatively extreme latitude, the variance in daylight hours might be, for example, 9 hours of daylight in the dead of winter, and 14 hours in the middle of summer. That would put sunrise and sunset 4.5 hours on either side of noon in winter—7:30 am and 4:30 pm—and 7 hours on either side in summer—5:00 am and 7:00 pm in winter.

If we make two reasonable assumptions—that people wake up at the same time year round, and that people don’t like waking up before sunrise—then we should find people waking up around 7:30 am throughout the year (and going to bed around 11:30 pm). In the winter months, this is perfect—but by the time summer rolls around, people are sleeping through several hours of sunshine in the morning. Since people (according to our assumption) aren’t going to naturally wake up earlier on their own, we introduce the “lying clock” to pretend that 6:30 is really 7:30. So now people are waking up at 6:30 am and going to bed at 10:30 pm, and they get an “extra” hour of sunlight during their day.

Note that, with this model, switching to use Daylight Saving Time year-round doesn’t help any, because now you’ve put sunrise in the winter at 8:30 am. People don’t want to wake up in the dark, so you’re back to square one.

It’s too bad they don’t, though. I read an intriguing (if tongue-in-cheek) proposal on Slashdot during my reading on the subject. The idea was that, instead of tying winter sunrise to 7:30 am (and the sun’s zenith at noon), instead stick it around 1 pm (with the summer sunset falling around 10:30 am). The thought is that if people could be persuaded to get out of bed and do their daily commute in the dark (which many people do in the winter anyway), they’d be treated with a beautiful sunrise on their lunch break every day, and after they get off work they’d still have plenty of sunlight even in the wintertime (the sun would set around 10 pm), and in the summertime they’d be going to sleep with sunlight to spare even if they partied until midnight. You’d have the core sunlight hours of the day during the hours when you’re most likely to be outside enjoying them.

I’m not quite sure I’m ready to switch to such a novel scheme (as I’m one of those stubborn folks who hates waking up when it’s dark outside), but it certainly would be nice to have as much daylight as I cared to spend, every day, 365 days a year.

This entry was posted on Friday, March 7th, 2008 at 10:33 pm and is filed under politics. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

One Response to “Summer Time”

Day light saving « Nori’s Kokorokara-Arigatou Weblog says:
March 9th, 2008 at 6:36 pm
[…] Daylight Extending“だよねって言ったら“Evening Daylight Extension Time,” […]