Saving Time (DST) ends at 2:00 am local time this coming Sunday morning in most of the
U.S., whereupon we return to Standard Time (ST). The event, as with the beginning of
DST in March, always elicits a lot of debate over whether DST is necessary in the 21st
century. I would prefer to end the inane biannual ritual for reasons illustrated in the
graph I created in Excel*.
Daylight Saving Time is
not observed everywhere across the globe, and where it is observed
there are variations in when it begins and ends. In the U.S., DST begins the second Sunday
of March and ends on the first Sunday in November (which is this coming weekend). Only
Arizona and Hawaii
do not participate.
To begin with, look at the chart titled "Daylight Saving Time Comparison." The overall
amount of daylight and darkness does not change on any given day or any given location
for ST, DST, or -DST, only the clock times of those occurrences. Two complete years are
plotted for three cases:
- Standard Time all year (ST, green line). Note
the time difference between the curve maximum and minimum for comparison to the other
two cases (both for sunrise and for sunset).
- Daylight Saving Time in the manner currently implemented in the U.S., with changeovers
occurring as noted above (DST, blue line); i.e.,
an hour is added on the 2nd Sunday of March and removed on the 1st Sunday of November.
Note that the time difference between the max/min for the clock time of sunset is much
greater than the ST value. Note also that the time difference between the max/min for
the clock time of sunrise is much less than the ST value.
- Daylight Saving Time opposite of the manner currently implemented in the U.S., with
changeovers occurring as noted above (-DST, red line);
i.e., an hour is subtracted on the 2nd Sunday of March and removed on the 1st Sunday
of November. Note that the variation in amplitudes of sunrise and sunset are reversed.
Personally, I find the amplified differences in the times of sunset because of DST
to be annoying. Swapping to the -DST system (my invention)
solves the problem and reduces the sunset clock time variation throughout the year, but
then the clock time of sunrise exhibits the amplified variations. That situation could
prove to be equally annoying to people who are awake more in the morning hours than in
the evening hours. The blackout curtains on my bedroom windows would effectively mask
the early morning sunlight caused by the -DST system, so I would prefer it over DST if
we must endure a time switch. However, I would much rather prefer that we dispose of
Daylight Saving Time altogether. It simply is not required in the 21st century.
DST was first implemented in the early 20th century when the U.S. was more of an agricultural
society and the argument was to give farmers more daylight in the morning when they traditionally
performed most chores ... or to conserve energy in wartimes, depending on
you believe. Congress has adjusted the start and stop dates multiple times in the
last century, and even did away with it for a while, only to bring it back during the
energy crisis in the 1970s. It is time (pun intended) to
do away with it for good.
* Data obtained from the the
I created a second chart that does not pertain to Daylight Saving Time, but instead
illustrates how the latitude on which you live affects the amount of daylight and darkness
you experience throughout the year. Sunrise and sunset clock times were plotted for three
widely varying latitudes in the U.S.: Miami, Florida;
Kernersville, North Carolina (where I live); and Portland, Maine.
As shown, the nearer to the equator you are located, the less the variation in day/night
throughout the year, and the nearer to the poles you are located, the more the variation.
At the Arctic and Antarctic circles, there is no sunrise on the winter
solstice and there
is no sunset on the summer solstice. At greater latitudes you will experience the 'midnight sun' on
days surrounding the summer solstice. For a given latitude, changes in longitude does
not affect the amount of daylight and darkness on a given day, only the clock time at
which they occur.
You might also be interested in an article I wrote a couple years later titled, "Daylight
Saving(s) Time vs. Standard Time."
Posted October 31, 2014